1 \define{versionidconfig} \versionid $Id$
3 \C{config} Configuring PuTTY
5 This chapter describes all the \i{configuration options} in PuTTY.
7 PuTTY is configured using the control panel that comes up before you
8 start a session. Some options can also be changed in the middle of a
9 session, by selecting \q{Change Settings} from the window menu.
11 \H{config-session} The Session panel
13 The Session configuration panel contains the basic options you need
14 to specify in order to open a session at all, and also allows you to
15 save your settings to be reloaded later.
17 \S{config-hostname} The \i{host name} section
19 \cfg{winhelp-topic}{session.hostname}
21 The top box on the Session panel, labelled \q{Specify your
22 connection by host name}, contains the details that need to be
23 filled in before PuTTY can open a session at all.
25 \b The \q{Host Name} box is where you type the name, or the \i{IP
26 address}, of the server you want to connect to.
28 \b The \q{Connection type} radio buttons let you choose what type of
29 connection you want to make: a \I{raw TCP connections}raw
30 connection, a \i{Telnet} connection, an \i{Rlogin} connection, an
31 \i{SSH} connection, or a connection to a local \i{serial line}. (See
32 \k{which-one} for a summary of the differences between SSH, Telnet
33 and rlogin; see \k{using-rawprot} for an explanation of \q{raw}
34 connections; see \k{using-serial} for information about using a
37 \b The \q{Port} box lets you specify which \i{port number} on the
38 server to connect to. If you select Telnet, Rlogin, or SSH, this box
39 will be filled in automatically to the usual value, and you will
40 only need to change it if you have an unusual server. If you select
41 Raw mode, you will almost certainly need to fill in the \q{Port} box
44 If you select \q{Serial} from the \q{Connection type} radio buttons,
45 the \q{Host Name} and \q{Port} boxes are replaced by \q{Serial line}
46 and \q{Speed}; see \k{config-serial} for more details of these.
48 \S{config-saving} \ii{Loading and storing saved sessions}
50 \cfg{winhelp-topic}{session.saved}
52 The next part of the Session configuration panel allows you to save
53 your preferred PuTTY options so they will appear automatically the
54 next time you start PuTTY. It also allows you to create \e{saved
55 sessions}, which contain a full set of configuration options plus a
56 host name and protocol. A saved session contains all the information
57 PuTTY needs to start exactly the session you want.
59 \b To save your default settings: first set up the settings the way
60 you want them saved. Then come back to the Session panel. Select the
61 \q{\i{Default Settings}} entry in the saved sessions list, with a single
62 click. Then press the \q{Save} button.
64 If there is a specific host you want to store the details of how to
65 connect to, you should create a saved session, which will be
66 separate from the Default Settings.
68 \b To save a session: first go through the rest of the configuration
69 box setting up all the options you want. Then come back to the
70 Session panel. Enter a name for the saved session in the \q{Saved
71 Sessions} input box. (The server name is often a good choice for a
72 saved session name.) Then press the \q{Save} button. Your saved
73 session name should now appear in the list box.
76 You can also save settings in mid-session, from the \q{Change Settings}
77 dialog. Settings changed since the start of the session will be saved
78 with their current values; as well as settings changed through the
79 dialog, this includes changes in window size, window title changes
80 sent by the server, and so on.
83 \b To reload a saved session: single-click to select the session
84 name in the list box, and then press the \q{Load} button. Your saved
85 settings should all appear in the configuration panel.
87 \b To modify a saved session: first load it as described above. Then
88 make the changes you want. Come back to the Session panel, and press
89 the \q{Save} button. The new settings will be saved over the top of
93 To save the new settings under a different name, you can enter the new
94 name in the \q{Saved Sessions} box, or single-click to select a
95 session name in the list box to overwrite that session. To save
96 \q{Default Settings}, you must single-click the name before saving.
99 \b To start a saved session immediately: double-click on the session
100 name in the list box.
102 \b To delete a saved session: single-click to select the session
103 name in the list box, and then press the \q{Delete} button.
105 Each saved session is independent of the Default Settings
106 configuration. If you change your preferences and update Default
107 Settings, you must also update every saved session separately.
109 Saved sessions are stored in the \i{Registry}, at the location
111 \c HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\Sessions
113 If you need to store them in a file, you could try the method
114 described in \k{config-file}.
116 \S{config-closeonexit} \q{\ii{Close Window} on Exit}
118 \cfg{winhelp-topic}{session.coe}
120 Finally in the Session panel, there is an option labelled \q{Close
121 Window on Exit}. This controls whether the PuTTY \i{terminal window}
122 disappears as soon as the session inside it terminates. If you are
123 likely to want to copy and paste text out of the session after it
124 has terminated, or restart the session, you should arrange for this
127 \q{Close Window On Exit} has three settings. \q{Always} means always
128 close the window on exit; \q{Never} means never close on exit
129 (always leave the window open, but \I{inactive window}inactive). The
130 third setting, and the default one, is \q{Only on clean exit}. In this
131 mode, a session which terminates normally will cause its window to
132 close, but one which is aborted unexpectedly by network trouble or a
133 confusing message from the server will leave the window up.
135 \H{config-logging} The Logging panel
137 \cfg{winhelp-topic}{logging.main}
139 The Logging configuration panel allows you to save \i{log file}s of your
140 PuTTY sessions, for debugging, analysis or future reference.
142 The main option is a radio-button set that specifies whether PuTTY
143 will log anything at all. The options are:
145 \b \q{None}. This is the default option; in this mode PuTTY will not
146 create a log file at all.
148 \b \q{Printable output}. In this mode, a log file will be
149 created and written to, but only printable text will be saved into
150 it. The various terminal control codes that are typically sent down
151 an interactive session alongside the printable text will be omitted.
152 This might be a useful mode if you want to read a log file in a text
153 editor and hope to be able to make sense of it.
155 \b \q{All session output}. In this mode, \e{everything} sent by
156 the server into your terminal session is logged. If you view the log
157 file in a text editor, therefore, you may well find it full of
158 strange control characters. This is a particularly useful mode if
159 you are experiencing problems with PuTTY's terminal handling: you
160 can record everything that went to the terminal, so that someone
161 else can replay the session later in slow motion and watch to see
164 \b \I{SSH packet log}\q{SSH packets}. In this mode (which is only used
165 by SSH connections), the SSH message packets sent over the encrypted
166 connection are written to the log file (as well as \i{Event Log}
167 entries). You might need this to debug a network-level problem, or
168 more likely to send to the PuTTY authors as part of a bug report.
169 \e{BE WARNED} that if you log in using a password, the password can
170 appear in the log file; see \k{config-logssh} for options that may
171 help to remove sensitive material from the log file before you send it
174 \b \q{SSH packets and raw data}. In this mode, as well as the
175 decrypted packets (as in the previous mode), the \e{raw} (encrypted,
176 compressed, etc) packets are \e{also} logged. This could be useful to
177 diagnose corruption in transit. (The same caveats as the previous mode
180 Note that the non-SSH logging options (\q{Printable output} and
181 \q{All session output}) only work with PuTTY proper; in programs
182 without terminal emulation (such as Plink), they will have no effect,
183 even if enabled via saved settings.
185 \S{config-logfilename} \q{Log file name}
187 \cfg{winhelp-topic}{logging.filename}
189 In this edit box you enter the name of the file you want to log the
190 session to. The \q{Browse} button will let you look around your file
191 system to find the right place to put the file; or if you already
192 know exactly where you want it to go, you can just type a pathname
195 There are a few special features in this box. If you use the \c{&}
196 character in the file name box, PuTTY will insert details of the
197 current session in the name of the file it actually opens. The
198 precise replacements it will do are:
200 \b \c{&Y} will be replaced by the current year, as four digits.
202 \b \c{&M} will be replaced by the current month, as two digits.
204 \b \c{&D} will be replaced by the current day of the month, as two
207 \b \c{&T} will be replaced by the current time, as six digits
208 (HHMMSS) with no punctuation.
210 \b \c{&H} will be replaced by the host name you are connecting to.
212 For example, if you enter the host name
213 \c{c:\\puttylogs\\log-&h-&y&m&d-&t.dat}, you will end up with files looking
216 \c log-server1.example.com-20010528-110859.dat
217 \c log-unixbox.somewhere.org-20010611-221001.dat
219 \S{config-logfileexists} \q{What to do if the log file already exists}
221 \cfg{winhelp-topic}{logging.exists}
223 This control allows you to specify what PuTTY should do if it tries
224 to start writing to a log file and it finds the file already exists.
225 You might want to automatically destroy the existing log file and
226 start a new one with the same name. Alternatively, you might want to
227 open the existing log file and add data to the \e{end} of it.
228 Finally (the default option), you might not want to have any
229 automatic behaviour, but to ask the user every time the problem
232 \S{config-logflush} \I{log file, flushing}\q{Flush log file frequently}
234 \cfg{winhelp-topic}{logging.flush}
236 This option allows you to control how frequently logged data is
237 flushed to disc. By default, PuTTY will flush data as soon as it is
238 displayed, so that if you view the log file while a session is still
239 open, it will be up to date; and if the client system crashes, there's
240 a greater chance that the data will be preserved.
242 However, this can incur a performance penalty. If PuTTY is running
243 slowly with logging enabled, you could try unchecking this option. Be
244 warned that the log file may not always be up to date as a result
245 (although it will of course be flushed when it is closed, for instance
246 at the end of a session).
248 \S{config-logssh} Options specific to \i{SSH packet log}ging
250 These options only apply if SSH packet data is being logged.
252 The following options allow particularly sensitive portions of
253 unencrypted packets to be automatically left out of the log file.
254 They are only intended to deter casual nosiness; an attacker could
255 glean a lot of useful information from even these obfuscated logs
256 (e.g., length of password).
258 \S2{config-logssh-omitpw} \q{Omit known password fields}
260 \cfg{winhelp-topic}{logging.ssh.omitpassword}
262 When checked, decrypted password fields are removed from the log of
263 transmitted packets. (This includes any user responses to
264 challenge-response authentication methods such as
265 \q{keyboard-interactive}.) This does not include X11 authentication
266 data if using X11 forwarding.
268 Note that this will only omit data that PuTTY \e{knows} to be a
269 password. However, if you start another login session within your
270 PuTTY session, for instance, any password used will appear in the
271 clear in the packet log. The next option may be of use to protect
274 This option is enabled by default.
276 \S2{config-logssh-omitdata} \q{Omit session data}
278 \cfg{winhelp-topic}{logging.ssh.omitdata}
280 When checked, all decrypted \q{session data} is omitted; this is
281 defined as data in terminal sessions and in forwarded channels (TCP,
282 X11, and authentication agent). This will usually substantially reduce
283 the size of the resulting log file.
285 This option is disabled by default.
287 \H{config-terminal} The Terminal panel
289 The Terminal configuration panel allows you to control the behaviour
290 of PuTTY's \i{terminal emulation}.
292 \S{config-autowrap} \q{Auto wrap mode initially on}
294 \cfg{winhelp-topic}{terminal.autowrap}
296 \ii{Auto wrap mode} controls what happens when text printed in a PuTTY
297 window reaches the right-hand edge of the window.
299 With auto wrap mode on, if a long line of text reaches the
300 right-hand edge, it will wrap over on to the next line so you can
301 still see all the text. With auto wrap mode off, the cursor will
302 stay at the right-hand edge of the screen, and all the characters in
303 the line will be printed on top of each other.
305 If you are running a full-screen application and you occasionally
306 find the screen scrolling up when it looks as if it shouldn't, you
307 could try turning this option off.
309 Auto wrap mode can be turned on and off by \i{control sequence}s sent by
310 the server. This configuration option controls the \e{default}
311 state, which will be restored when you reset the terminal (see
312 \k{reset-terminal}). However, if you modify this option in
313 mid-session using \q{Change Settings}, it will take effect
316 \S{config-decom} \q{DEC Origin Mode initially on}
318 \cfg{winhelp-topic}{terminal.decom}
320 \i{DEC Origin Mode} is a minor option which controls how PuTTY
321 interprets cursor-position \i{control sequence}s sent by the server.
323 The server can send a control sequence that restricts the \i{scrolling
324 region} of the display. For example, in an editor, the server might
325 reserve a line at the top of the screen and a line at the bottom,
326 and might send a control sequence that causes scrolling operations
327 to affect only the remaining lines.
329 With DEC Origin Mode on, \i{cursor coordinates} are counted from the top
330 of the scrolling region. With it turned off, cursor coordinates are
331 counted from the top of the whole screen regardless of the scrolling
334 It is unlikely you would need to change this option, but if you find
335 a full-screen application is displaying pieces of text in what looks
336 like the wrong part of the screen, you could try turning DEC Origin
337 Mode on to see whether that helps.
339 DEC Origin Mode can be turned on and off by control sequences sent
340 by the server. This configuration option controls the \e{default}
341 state, which will be restored when you reset the terminal (see
342 \k{reset-terminal}). However, if you modify this option in
343 mid-session using \q{Change Settings}, it will take effect
346 \S{config-crlf} \q{Implicit CR in every LF}
348 \cfg{winhelp-topic}{terminal.lfhascr}
350 Most servers send two control characters, \i{CR} and \i{LF}, to start a
351 \i{new line} of the screen. The CR character makes the cursor return to the
352 left-hand side of the screen. The LF character makes the cursor move
353 one line down (and might make the screen scroll).
355 Some servers only send LF, and expect the terminal to move the
356 cursor over to the left automatically. If you come across a server
357 that does this, you will see a \I{stair-stepping}stepped effect on the
360 \c First line of text
364 If this happens to you, try enabling the \q{Implicit CR in every LF}
365 option, and things might go back to normal:
367 \c First line of text
371 \S{config-erase} \q{Use \i{background colour} to erase screen}
373 \cfg{winhelp-topic}{terminal.bce}
375 Not all terminals agree on what colour to turn the screen when the
376 server sends a \q{\i{clear screen}} sequence. Some terminals believe the
377 screen should always be cleared to the \e{default} background
378 colour. Others believe the screen should be cleared to whatever the
379 server has selected as a background colour.
381 There exist applications that expect both kinds of behaviour.
382 Therefore, PuTTY can be configured to do either.
384 With this option disabled, screen clearing is always done in the
385 default background colour. With this option enabled, it is done in
386 the \e{current} background colour.
388 Background-colour erase can be turned on and off by \i{control
389 sequences} sent by the server. This configuration option controls the
390 \e{default} state, which will be restored when you reset the
391 terminal (see \k{reset-terminal}). However, if you modify this
392 option in mid-session using \q{Change Settings}, it will take effect
395 \S{config-blink} \q{Enable \i{blinking text}}
397 \cfg{winhelp-topic}{terminal.blink}
399 The server can ask PuTTY to display text that blinks on and off.
400 This is very distracting, so PuTTY allows you to turn blinking text
403 When blinking text is disabled and the server attempts to make some
404 text blink, PuTTY will instead display the text with a \I{background
405 colour, bright}bolded background colour.
407 Blinking text can be turned on and off by \i{control sequence}s sent by
408 the server. This configuration option controls the \e{default}
409 state, which will be restored when you reset the terminal (see
410 \k{reset-terminal}). However, if you modify this option in
411 mid-session using \q{Change Settings}, it will take effect
414 \S{config-answerback} \q{\ii{Answerback} to ^E}
416 \cfg{winhelp-topic}{terminal.answerback}
418 This option controls what PuTTY will send back to the server if the
419 server sends it the ^E \i{enquiry character}. Normally it just sends
420 the string \q{PuTTY}.
422 If you accidentally write the contents of a binary file to your
423 terminal, you will probably find that it contains more than one ^E
424 character, and as a result your next command line will probably read
425 \q{PuTTYPuTTYPuTTY...} as if you had typed the answerback string
426 multiple times at the keyboard. If you set the answerback string to
427 be empty, this problem should go away, but doing so might cause
430 Note that this is \e{not} the feature of PuTTY which the server will
431 typically use to determine your terminal type. That feature is the
432 \q{\ii{Terminal-type} string} in the Connection panel; see
433 \k{config-termtype} for details.
435 You can include control characters in the answerback string using
436 \c{^C} notation. (Use \c{^~} to get a literal \c{^}.)
438 \S{config-localecho} \q{\ii{Local echo}}
440 \cfg{winhelp-topic}{terminal.localecho}
442 With local echo disabled, characters you type into the PuTTY window
443 are not echoed in the window \e{by PuTTY}. They are simply sent to
444 the server. (The \e{server} might choose to \I{remote echo}echo them
445 back to you; this can't be controlled from the PuTTY control panel.)
447 Some types of session need local echo, and many do not. In its
448 default mode, PuTTY will automatically attempt to deduce whether or
449 not local echo is appropriate for the session you are working in. If
450 you find it has made the wrong decision, you can use this
451 configuration option to override its choice: you can force local
452 echo to be turned on, or force it to be turned off, instead of
453 relying on the automatic detection.
455 \S{config-localedit} \q{\ii{Local line editing}}
457 \cfg{winhelp-topic}{terminal.localedit}
459 Normally, every character you type into the PuTTY window is sent
460 immediately to the server the moment you type it.
462 If you enable local line editing, this changes. PuTTY will let you
463 edit a whole line at a time locally, and the line will only be sent
464 to the server when you press Return. If you make a mistake, you can
465 use the Backspace key to correct it before you press Return, and the
466 server will never see the mistake.
468 Since it is hard to edit a line locally without being able to see
469 it, local line editing is mostly used in conjunction with \i{local echo}
470 (\k{config-localecho}). This makes it ideal for use in raw mode
471 \#{FIXME} or when connecting to \i{MUD}s or \i{talker}s. (Although some more
472 advanced MUDs do occasionally turn local line editing on and turn
473 local echo off, in order to accept a password from the user.)
475 Some types of session need local line editing, and many do not. In
476 its default mode, PuTTY will automatically attempt to deduce whether
477 or not local line editing is appropriate for the session you are
478 working in. If you find it has made the wrong decision, you can use
479 this configuration option to override its choice: you can force
480 local line editing to be turned on, or force it to be turned off,
481 instead of relying on the automatic detection.
483 \S{config-printing} \ii{Remote-controlled printing}
485 \cfg{winhelp-topic}{terminal.printing}
487 A lot of VT100-compatible terminals support printing under control
488 of the remote server. PuTTY supports this feature as well, but it is
489 turned off by default.
491 To enable remote-controlled printing, choose a printer from the
492 \q{Printer to send ANSI printer output to} drop-down list box. This
493 should allow you to select from all the printers you have installed
494 drivers for on your computer. Alternatively, you can type the
495 network name of a networked printer (for example,
496 \c{\\\\printserver\\printer1}) even if you haven't already
497 installed a driver for it on your own machine.
499 When the remote server attempts to print some data, PuTTY will send
500 that data to the printer \e{raw} - without translating it,
501 attempting to format it, or doing anything else to it. It is up to
502 you to ensure your remote server knows what type of printer it is
505 Since PuTTY sends data to the printer raw, it cannot offer options
506 such as portrait versus landscape, print quality, or paper tray
507 selection. All these things would be done by your PC printer driver
508 (which PuTTY bypasses); if you need them done, you will have to find
509 a way to configure your remote server to do them.
511 To disable remote printing again, choose \q{None (printing
512 disabled)} from the printer selection list. This is the default
515 \H{config-keyboard} The Keyboard panel
517 The Keyboard configuration panel allows you to control the behaviour
518 of the \i{keyboard} in PuTTY. The correct state for many of these
519 settings depends on what the server to which PuTTY is connecting
520 expects. With a \i{Unix} server, this is likely to depend on the
521 \i\c{termcap} or \i\c{terminfo} entry it uses, which in turn is likely to
522 be controlled by the \q{\ii{Terminal-type} string} setting in the Connection
523 panel; see \k{config-termtype} for details. If none of the settings here
524 seems to help, you may find \k{faq-keyboard} to be useful.
526 \S{config-backspace} Changing the action of the \ii{Backspace key}
528 \cfg{winhelp-topic}{keyboard.backspace}
530 Some terminals believe that the Backspace key should send the same
531 thing to the server as \i{Control-H} (ASCII code 8). Other terminals
532 believe that the Backspace key should send ASCII code 127 (usually
533 known as \i{Control-?}) so that it can be distinguished from Control-H.
534 This option allows you to choose which code PuTTY generates when you
537 If you are connecting over SSH, PuTTY by default tells the server
538 the value of this option (see \k{config-ttymodes}), so you may find
539 that the Backspace key does the right thing either way. Similarly,
540 if you are connecting to a \i{Unix} system, you will probably find that
541 the Unix \i\c{stty} command lets you configure which the server
542 expects to see, so again you might not need to change which one PuTTY
543 generates. On other systems, the server's expectation might be fixed
544 and you might have no choice but to configure PuTTY.
546 If you do have the choice, we recommend configuring PuTTY to
547 generate Control-? and configuring the server to expect it, because
548 that allows applications such as \c{emacs} to use Control-H for
551 (Typing \i{Shift-Backspace} will cause PuTTY to send whichever code
552 isn't configured here as the default.)
554 \S{config-homeend} Changing the action of the \i{Home and End keys}
556 \cfg{winhelp-topic}{keyboard.homeend}
558 The Unix terminal emulator \i\c{rxvt} disagrees with the rest of the
559 world about what character sequences should be sent to the server by
560 the Home and End keys.
562 \i\c{xterm}, and other terminals, send \c{ESC [1~} for the Home key,
563 and \c{ESC [4~} for the End key. \c{rxvt} sends \c{ESC [H} for the
564 Home key and \c{ESC [Ow} for the End key.
566 If you find an application on which the Home and End keys aren't
567 working, you could try switching this option to see if it helps.
569 \S{config-funkeys} Changing the action of the \i{function keys} and
572 \cfg{winhelp-topic}{keyboard.funkeys}
574 This option affects the function keys (F1 to F12) and the top row of
577 \b In the default mode, labelled \c{ESC [n~}, the function keys
578 generate sequences like \c{ESC [11~}, \c{ESC [12~} and so on. This
579 matches the general behaviour of Digital's terminals.
581 \b In Linux mode, F6 to F12 behave just like the default mode, but
582 F1 to F5 generate \c{ESC [[A} through to \c{ESC [[E}. This mimics the
583 \i{Linux virtual console}.
585 \b In \I{xterm}Xterm R6 mode, F5 to F12 behave like the default mode, but F1
586 to F4 generate \c{ESC OP} through to \c{ESC OS}, which are the
587 sequences produced by the top row of the \e{keypad} on Digital's
590 \b In \i{VT400} mode, all the function keys behave like the default
591 mode, but the actual top row of the numeric keypad generates \c{ESC
592 OP} through to \c{ESC OS}.
594 \b In \i{VT100+} mode, the function keys generate \c{ESC OP} through to
597 \b In \i{SCO} mode, the function keys F1 to F12 generate \c{ESC [M}
598 through to \c{ESC [X}. Together with shift, they generate \c{ESC [Y}
599 through to \c{ESC [j}. With control they generate \c{ESC [k} through
600 to \c{ESC [v}, and with shift and control together they generate
601 \c{ESC [w} through to \c{ESC [\{}.
603 If you don't know what any of this means, you probably don't need to
606 \S{config-appcursor} Controlling \i{Application Cursor Keys} mode
608 \cfg{winhelp-topic}{keyboard.appcursor}
610 Application Cursor Keys mode is a way for the server to change the
611 control sequences sent by the arrow keys. In normal mode, the arrow
612 keys send \c{ESC [A} through to \c{ESC [D}. In application mode,
613 they send \c{ESC OA} through to \c{ESC OD}.
615 Application Cursor Keys mode can be turned on and off by the server,
616 depending on the application. PuTTY allows you to configure the
619 You can also disable application cursor keys mode completely, using
620 the \q{Features} configuration panel; see
621 \k{config-features-application}.
623 \S{config-appkeypad} Controlling \i{Application Keypad} mode
625 \cfg{winhelp-topic}{keyboard.appkeypad}
627 Application Keypad mode is a way for the server to change the
628 behaviour of the numeric keypad.
630 In normal mode, the keypad behaves like a normal Windows keypad:
631 with \i{NumLock} on, the number keys generate numbers, and with NumLock
632 off they act like the arrow keys and Home, End etc.
634 In application mode, all the keypad keys send special control
635 sequences, \e{including} Num Lock. Num Lock stops behaving like Num
636 Lock and becomes another function key.
638 Depending on which version of Windows you run, you may find the Num
639 Lock light still flashes on and off every time you press Num Lock,
640 even when application mode is active and Num Lock is acting like a
641 function key. This is unavoidable.
643 Application keypad mode can be turned on and off by the server,
644 depending on the application. PuTTY allows you to configure the
647 You can also disable application keypad mode completely, using the
648 \q{Features} configuration panel; see
649 \k{config-features-application}.
651 \S{config-nethack} Using \i{NetHack keypad mode}
653 \cfg{winhelp-topic}{keyboard.nethack}
655 PuTTY has a special mode for playing NetHack. You can enable it by
656 selecting \q{NetHack} in the \q{Initial state of numeric keypad}
659 In this mode, the numeric keypad keys 1-9 generate the NetHack
660 movement commands (\cw{hjklyubn}). The 5 key generates the \c{.}
661 command (do nothing).
663 In addition, pressing Shift or Ctrl with the keypad keys generate
664 the Shift- or Ctrl-keys you would expect (e.g. keypad-7 generates
665 \cq{y}, so Shift-keypad-7 generates \cq{Y} and Ctrl-keypad-7
666 generates Ctrl-Y); these commands tell NetHack to keep moving you in
667 the same direction until you encounter something interesting.
669 For some reason, this feature only works properly when \i{Num Lock} is
670 on. We don't know why.
672 \S{config-compose} Enabling a DEC-like \ii{Compose key}
674 \cfg{winhelp-topic}{keyboard.compose}
676 DEC terminals have a Compose key, which provides an easy-to-remember
677 way of typing \i{accented characters}. You press Compose and then type
678 two more characters. The two characters are \q{combined} to produce
679 an accented character. The choices of character are designed to be
680 easy to remember; for example, composing \q{e} and \q{`} produces
681 the \q{\u00e8{e-grave}} character.
683 If your keyboard has a Windows \i{Application key}, it acts as a Compose
684 key in PuTTY. Alternatively, if you enable the \q{\i{AltGr} acts as
685 Compose key} option, the AltGr key will become a Compose key.
687 \S{config-ctrlalt} \q{Control-Alt is different from \i{AltGr}}
689 \cfg{winhelp-topic}{keyboard.ctrlalt}
691 Some old keyboards do not have an AltGr key, which can make it
692 difficult to type some characters. PuTTY can be configured to treat
693 the key combination Ctrl + Left Alt the same way as the AltGr key.
695 By default, this checkbox is checked, and the key combination Ctrl +
696 Left Alt does something completely different. PuTTY's usual handling
697 of the left Alt key is to prefix the Escape (Control-\cw{[})
698 character to whatever character sequence the rest of the keypress
699 would generate. For example, Alt-A generates Escape followed by
700 \c{a}. So Alt-Ctrl-A would generate Escape, followed by Control-A.
702 If you uncheck this box, Ctrl-Alt will become a synonym for AltGr,
703 so you can use it to type extra graphic characters if your keyboard
706 (However, Ctrl-Alt will never act as a Compose key, regardless of the
707 setting of \q{AltGr acts as Compose key} described in
710 \H{config-bell} The Bell panel
712 The Bell panel controls the \i{terminal bell} feature: the server's
713 ability to cause PuTTY to beep at you.
715 In the default configuration, when the server sends the character
716 with ASCII code 7 (Control-G), PuTTY will play the \i{Windows Default
717 Beep} sound. This is not always what you want the terminal bell
718 feature to do; the Bell panel allows you to configure alternative
721 \S{config-bellstyle} \q{Set the style of bell}
723 \cfg{winhelp-topic}{bell.style}
725 This control allows you to select various different actions to occur
728 \b Selecting \q{None} \I{terminal bell, disabling}disables the bell
729 completely. In this mode, the server can send as many Control-G
730 characters as it likes and nothing at all will happen.
732 \b \q{Make default system alert sound} is the default setting. It
733 causes the Windows \q{Default Beep} sound to be played. To change
734 what this sound is, or to test it if nothing seems to be happening,
735 use the Sound configurer in the Windows Control Panel.
737 \b \q{\ii{Visual bell}} is a silent alternative to a beeping computer. In
738 this mode, when the server sends a Control-G, the whole PuTTY window
739 will flash white for a fraction of a second.
741 \b \q{Beep using the \i{PC speaker}} is self-explanatory.
743 \b \q{Play a custom \i{sound file}} allows you to specify a particular
744 sound file to be used by PuTTY alone, or even by a particular
745 individual PuTTY session. This allows you to distinguish your PuTTY
746 beeps from any other beeps on the system. If you select this option,
747 you will also need to enter the name of your sound file in the edit
748 control \q{Custom sound file to play as a bell}.
750 \S{config-belltaskbar} \q{\ii{Taskbar}/\I{window caption}caption
753 \cfg{winhelp-topic}{bell.taskbar}
755 This feature controls what happens to the PuTTY window's entry in
756 the Windows Taskbar if a bell occurs while the window does not have
759 In the default state (\q{Disabled}) nothing unusual happens.
761 If you select \q{Steady}, then when a bell occurs and the window is
762 not in focus, the window's Taskbar entry and its title bar will
763 change colour to let you know that PuTTY session is asking for your
764 attention. The change of colour will persist until you select the
765 window, so you can leave several PuTTY windows minimised in your
766 terminal, go away from your keyboard, and be sure not to have missed
767 any important beeps when you get back.
769 \q{Flashing} is even more eye-catching: the Taskbar entry will
770 continuously flash on and off until you select the window.
772 \S{config-bellovl} \q{Control the \i{bell overload} behaviour}
774 \cfg{winhelp-topic}{bell.overload}
776 A common user error in a terminal session is to accidentally run the
777 Unix command \c{cat} (or equivalent) on an inappropriate file type,
778 such as an executable, image file, or ZIP file. This produces a huge
779 stream of non-text characters sent to the terminal, which typically
780 includes a lot of bell characters. As a result of this the terminal
781 often doesn't stop beeping for ten minutes, and everybody else in
782 the office gets annoyed.
784 To try to avoid this behaviour, or any other cause of excessive
785 beeping, PuTTY includes a bell overload management feature. In the
786 default configuration, receiving more than five bell characters in a
787 two-second period will cause the overload feature to activate. Once
788 the overload feature is active, further bells will \I{terminal bell,
789 disabling} have no effect at all, so the rest of your binary file
790 will be sent to the screen in silence. After a period of five seconds
791 during which no further bells are received, the overload feature will
792 turn itself off again and bells will be re-enabled.
794 If you want this feature completely disabled, you can turn it off
795 using the checkbox \q{Bell is temporarily disabled when over-used}.
797 Alternatively, if you like the bell overload feature but don't agree
798 with the settings, you can configure the details: how many bells
799 constitute an overload, how short a time period they have to arrive
800 in to do so, and how much silent time is required before the
801 overload feature will deactivate itself.
803 Bell overload mode is always deactivated by any keypress in the
804 terminal. This means it can respond to large unexpected streams of
805 data, but does not interfere with ordinary command-line activities
806 that generate beeps (such as filename completion).
808 \H{config-features} The Features panel
810 PuTTY's \i{terminal emulation} is very highly featured, and can do a lot
811 of things under remote server control. Some of these features can
812 cause problems due to buggy or strangely configured server
815 The Features configuration panel allows you to disable some of
816 PuTTY's more advanced terminal features, in case they cause trouble.
818 \S{config-features-application} Disabling application keypad and cursor keys
820 \cfg{winhelp-topic}{features.application}
822 \I{Application Keypad}Application keypad mode (see
823 \k{config-appkeypad}) and \I{Application Cursor Keys}application
824 cursor keys mode (see \k{config-appcursor}) alter the behaviour of
825 the keypad and cursor keys. Some applications enable these modes but
826 then do not deal correctly with the modified keys. You can force
827 these modes to be permanently disabled no matter what the server
830 \S{config-features-mouse} Disabling \cw{xterm}-style \i{mouse reporting}
832 \cfg{winhelp-topic}{features.mouse}
834 PuTTY allows the server to send \i{control codes} that let it take over
835 the mouse and use it for purposes other than \i{copy and paste}.
836 Applications which use this feature include the text-mode web
837 browser \i\c{links}, the Usenet newsreader \i\c{trn} version 4, and the
838 file manager \i\c{mc} (Midnight Commander).
840 If you find this feature inconvenient, you can disable it using the
841 \q{Disable xterm-style mouse reporting} control. With this box
842 ticked, the mouse will \e{always} do copy and paste in the normal
845 Note that even if the application takes over the mouse, you can
846 still manage PuTTY's copy and paste by holding down the Shift key
847 while you select and paste, unless you have deliberately turned this
848 feature off (see \k{config-mouseshift}).
850 \S{config-features-resize} Disabling remote \i{terminal resizing}
852 \cfg{winhelp-topic}{features.resize}
854 PuTTY has the ability to change the terminal's size and position in
855 response to commands from the server. If you find PuTTY is doing
856 this unexpectedly or inconveniently, you can tell PuTTY not to
857 respond to those server commands.
859 \S{config-features-altscreen} Disabling switching to the \i{alternate screen}
861 \cfg{winhelp-topic}{features.altscreen}
863 Many terminals, including PuTTY, support an \q{alternate screen}.
864 This is the same size as the ordinary terminal screen, but separate.
865 Typically a screen-based program such as a text editor might switch
866 the terminal to the alternate screen before starting up. Then at the
867 end of the run, it switches back to the primary screen, and you see
868 the screen contents just as they were before starting the editor.
870 Some people prefer this not to happen. If you want your editor to
871 run in the same screen as the rest of your terminal activity, you
872 can disable the alternate screen feature completely.
874 \S{config-features-retitle} Disabling remote \i{window title} changing
876 \cfg{winhelp-topic}{features.retitle}
878 PuTTY has the ability to change the window title in response to
879 commands from the server. If you find PuTTY is doing this
880 unexpectedly or inconveniently, you can tell PuTTY not to respond to
881 those server commands.
883 \S{config-features-qtitle} Response to remote \i{window title} querying
885 \cfg{winhelp-topic}{features.qtitle}
887 PuTTY can optionally provide the xterm service of allowing server
888 applications to find out the local window title. This feature is
889 disabled by default, but you can turn it on if you really want it.
891 NOTE that this feature is a \e{potential \i{security hazard}}. If a
892 malicious application can write data to your terminal (for example,
893 if you merely \c{cat} a file owned by someone else on the server
894 machine), it can change your window title (unless you have disabled
895 this as mentioned in \k{config-features-retitle}) and then use this
896 service to have the new window title sent back to the server as if
897 typed at the keyboard. This allows an attacker to fake keypresses
898 and potentially cause your server-side applications to do things you
899 didn't want. Therefore this feature is disabled by default, and we
900 recommend you do not set it to \q{Window title} unless you \e{really}
901 know what you are doing.
903 There are three settings for this option:
907 \dd PuTTY makes no response whatsoever to the relevant escape
908 sequence. This may upset server-side software that is expecting some
913 \dd PuTTY makes a well-formed response, but leaves it blank. Thus,
914 server-side software that expects a response is kept happy, but an
915 attacker cannot influence the response string. This is probably the
916 setting you want if you have no better ideas.
920 \dd PuTTY responds with the actual window title. This is dangerous for
921 the reasons described above.
923 \S{config-features-dbackspace} Disabling \i{destructive backspace}
925 \cfg{winhelp-topic}{features.dbackspace}
927 Normally, when PuTTY receives character 127 (^?) from the server, it
928 will perform a \q{destructive backspace}: move the cursor one space
929 left and delete the character under it. This can apparently cause
930 problems in some applications, so PuTTY provides the ability to
931 configure character 127 to perform a normal backspace (without
932 deleting a character) instead.
934 \S{config-features-charset} Disabling remote \i{character set}
937 \cfg{winhelp-topic}{features.charset}
939 PuTTY has the ability to change its character set configuration in
940 response to commands from the server. Some programs send these
941 commands unexpectedly or inconveniently. In particular, \I{BitchX} (an
942 IRC client) seems to have a habit of reconfiguring the character set
943 to something other than the user intended.
945 If you find that accented characters are not showing up the way you
946 expect them to, particularly if you're running BitchX, you could try
947 disabling the remote character set configuration commands.
949 \S{config-features-shaping} Disabling \i{Arabic text shaping}
951 \cfg{winhelp-topic}{features.arabicshaping}
953 PuTTY supports shaping of Arabic text, which means that if your
954 server sends text written in the basic \i{Unicode} Arabic alphabet then
955 it will convert it to the correct display forms before printing it
958 If you are using full-screen software which was not expecting this
959 to happen (especially if you are not an Arabic speaker and you
960 unexpectedly find yourself dealing with Arabic text files in
961 applications which are not Arabic-aware), you might find that the
962 \i{display becomes corrupted}. By ticking this box, you can disable
963 Arabic text shaping so that PuTTY displays precisely the characters
964 it is told to display.
966 You may also find you need to disable bidirectional text display;
967 see \k{config-features-bidi}.
969 \S{config-features-bidi} Disabling \i{bidirectional text} display
971 \cfg{winhelp-topic}{features.bidi}
973 PuTTY supports bidirectional text display, which means that if your
974 server sends text written in a language which is usually displayed
975 from right to left (such as \i{Arabic} or \i{Hebrew}) then PuTTY will
976 automatically flip it round so that it is displayed in the right
977 direction on the screen.
979 If you are using full-screen software which was not expecting this
980 to happen (especially if you are not an Arabic speaker and you
981 unexpectedly find yourself dealing with Arabic text files in
982 applications which are not Arabic-aware), you might find that the
983 \i{display becomes corrupted}. By ticking this box, you can disable
984 bidirectional text display, so that PuTTY displays text from left to
985 right in all situations.
987 You may also find you need to disable Arabic text shaping;
988 see \k{config-features-shaping}.
990 \H{config-window} The Window panel
992 The Window configuration panel allows you to control aspects of the
995 \S{config-winsize} Setting the \I{window size}size of the PuTTY window
997 \cfg{winhelp-topic}{window.size}
999 The \q{\ii{Columns}} and \q{\ii{Rows}} boxes let you set the PuTTY
1000 window to a precise size. Of course you can also \I{window resizing}drag
1001 the window to a new size while a session is running.
1003 \S{config-winsizelock} What to do when the window is resized
1005 \cfg{winhelp-topic}{window.resize}
1007 These options allow you to control what happens when the user tries
1008 to \I{window resizing}resize the PuTTY window using its window furniture.
1010 There are four options here:
1012 \b \q{Change the number of rows and columns}: the font size will not
1013 change. (This is the default.)
1015 \b \q{Change the size of the font}: the number of rows and columns in
1016 the terminal will stay the same, and the \i{font size} will change.
1018 \b \q{Change font size when maximised}: when the window is resized,
1019 the number of rows and columns will change, \e{except} when the window
1020 is \i{maximise}d (or restored), when the font size will change.
1022 \b \q{Forbid resizing completely}: the terminal will refuse to be
1025 \S{config-scrollback} Controlling \i{scrollback}
1027 \cfg{winhelp-topic}{window.scrollback}
1029 These options let you configure the way PuTTY keeps text after it
1030 scrolls off the top of the screen (see \k{using-scrollback}).
1032 The \q{Lines of scrollback} box lets you configure how many lines of
1033 text PuTTY keeps. The \q{Display scrollbar} options allow you to
1034 hide the \i{scrollbar} (although you can still view the scrollback using
1035 the keyboard as described in \k{using-scrollback}). You can separately
1036 configure whether the scrollbar is shown in \i{full-screen} mode and in
1039 If you are viewing part of the scrollback when the server sends more
1040 text to PuTTY, the screen will revert to showing the current
1041 terminal contents. You can disable this behaviour by turning off
1042 \q{Reset scrollback on display activity}. You can also make the
1043 screen revert when you press a key, by turning on \q{Reset
1044 scrollback on keypress}.
1046 \S{config-erasetoscrollback} \q{Push erased text into scrollback}
1048 \cfg{winhelp-topic}{window.erased}
1050 When this option is enabled, the contents of the terminal screen
1051 will be pushed into the scrollback when a server-side application
1052 clears the screen, so that your scrollback will contain a better
1053 record of what was on your screen in the past.
1055 If the application switches to the \i{alternate screen} (see
1056 \k{config-features-altscreen} for more about this), then the
1057 contents of the primary screen will be visible in the scrollback
1058 until the application switches back again.
1060 This option is enabled by default.
1062 \H{config-appearance} The Appearance panel
1064 The Appearance configuration panel allows you to control aspects of
1065 the appearance of \I{PuTTY window}PuTTY's window.
1067 \S{config-cursor} Controlling the appearance of the \i{cursor}
1069 \cfg{winhelp-topic}{appearance.cursor}
1071 The \q{Cursor appearance} option lets you configure the cursor to be
1072 a block, an underline, or a vertical line. A block cursor becomes an
1073 empty box when the window loses focus; an underline or a vertical
1074 line becomes dotted.
1076 The \q{\ii{Cursor blinks}} option makes the cursor blink on and off. This
1077 works in any of the cursor modes.
1079 \S{config-font} Controlling the \i{font} used in the terminal window
1081 \cfg{winhelp-topic}{appearance.font}
1083 This option allows you to choose what font, in what \I{font size}size,
1084 the PuTTY terminal window uses to display the text in the session. You
1085 will be offered a choice from all the fixed-width fonts installed on the
1086 system. (VT100-style terminal handling can only deal with fixed-width
1089 \S{config-mouseptr} \q{Hide \i{mouse pointer} when typing in window}
1091 \cfg{winhelp-topic}{appearance.hidemouse}
1093 If you enable this option, the mouse pointer will disappear if the
1094 PuTTY window is selected and you press a key. This way, it will not
1095 obscure any of the text in the window while you work in your
1096 session. As soon as you move the mouse, the pointer will reappear.
1098 This option is disabled by default, so the mouse pointer remains
1099 visible at all times.
1101 \S{config-winborder} Controlling the \i{window border}
1103 \cfg{winhelp-topic}{appearance.border}
1105 PuTTY allows you to configure the appearance of the window border to
1108 The checkbox marked \q{Sunken-edge border} changes the appearance of
1109 the window border to something more like a DOS box: the inside edge
1110 of the border is highlighted as if it sank down to meet the surface
1111 inside the window. This makes the border a little bit thicker as
1112 well. It's hard to describe well. Try it and see if you like it.
1114 You can also configure a completely blank gap between the text in
1115 the window and the border, using the \q{Gap between text and window
1116 edge} control. By default this is set at one pixel. You can reduce
1117 it to zero, or increase it further.
1119 \H{config-behaviour} The Behaviour panel
1121 The Behaviour configuration panel allows you to control aspects of
1122 the behaviour of \I{PuTTY window}PuTTY's window.
1124 \S{config-title} Controlling the \i{window title}
1126 \cfg{winhelp-topic}{appearance.title}
1128 The \q{Window title} edit box allows you to set the title of the
1129 PuTTY window. By default the window title will contain the \i{host name}
1130 followed by \q{PuTTY}, for example \c{server1.example.com - PuTTY}.
1131 If you want a different window title, this is where to set it.
1133 PuTTY allows the server to send \c{xterm} \i{control sequence}s which
1134 modify the title of the window in mid-session (unless this is disabled -
1135 see \k{config-features-retitle}); the title string set here
1136 is therefore only the \e{initial} window title.
1138 As well as the \e{window} title, there is also an \c{xterm}
1139 sequence to modify the \I{icon title}title of the window's \e{icon}.
1140 This makes sense in a windowing system where the window becomes an
1141 icon when minimised, such as Windows 3.1 or most X Window System
1142 setups; but in the Windows 95-like user interface it isn't as
1145 By default, PuTTY only uses the server-supplied \e{window} title, and
1146 ignores the icon title entirely. If for some reason you want to see
1147 both titles, check the box marked \q{Separate window and icon titles}.
1148 If you do this, PuTTY's window title and Taskbar \I{window caption}caption will
1149 change into the server-supplied icon title if you \i{minimise} the PuTTY
1150 window, and change back to the server-supplied window title if you
1151 restore it. (If the server has not bothered to supply a window or
1152 icon title, none of this will happen.)
1154 \S{config-warnonclose} \q{Warn before \i{closing window}}
1156 \cfg{winhelp-topic}{behaviour.closewarn}
1158 If you press the \i{Close button} in a PuTTY window that contains a
1159 running session, PuTTY will put up a warning window asking if you
1160 really meant to close the window. A window whose session has already
1161 terminated can always be closed without a warning.
1163 If you want to be able to close a window quickly, you can disable
1164 the \q{Warn before closing window} option.
1166 \S{config-altf4} \q{Window closes on \i{ALT-F4}}
1168 \cfg{winhelp-topic}{behaviour.altf4}
1170 By default, pressing ALT-F4 causes the \I{closing window}window to
1171 close (or a warning box to appear; see \k{config-warnonclose}). If you
1172 disable the \q{Window closes on ALT-F4} option, then pressing ALT-F4
1173 will simply send a key sequence to the server.
1175 \S{config-altspace} \q{\ii{System menu} appears on \i{ALT-Space}}
1177 \cfg{winhelp-topic}{behaviour.altspace}
1179 If this option is enabled, then pressing ALT-Space will bring up the
1180 PuTTY window's menu, like clicking on the top left corner. If it is
1181 disabled, then pressing ALT-Space will just send \c{ESC SPACE} to
1184 Some \i{accessibility} programs for Windows may need this option
1185 enabling to be able to control PuTTY's window successfully. For
1186 instance, \i{Dragon NaturallySpeaking} requires it both to open the
1187 system menu via voice, and to close, minimise, maximise and restore
1190 \S{config-altonly} \q{\ii{System menu} appears on \i{Alt} alone}
1192 \cfg{winhelp-topic}{behaviour.altonly}
1194 If this option is enabled, then pressing and releasing ALT will
1195 bring up the PuTTY window's menu, like clicking on the top left
1196 corner. If it is disabled, then pressing and releasing ALT will have
1199 \S{config-alwaysontop} \q{Ensure window is \i{always on top}}
1201 \cfg{winhelp-topic}{behaviour.alwaysontop}
1203 If this option is enabled, the PuTTY window will stay on top of all
1206 \S{config-fullscreen} \q{\ii{Full screen} on Alt-Enter}
1208 \cfg{winhelp-topic}{behaviour.altenter}
1210 If this option is enabled, then pressing Alt-Enter will cause the
1211 PuTTY window to become full-screen. Pressing Alt-Enter again will
1212 restore the previous window size.
1214 The full-screen feature is also available from the \ii{System menu}, even
1215 when it is configured not to be available on the Alt-Enter key. See
1216 \k{using-fullscreen}.
1218 \H{config-translation} The Translation panel
1220 The Translation configuration panel allows you to control the
1221 translation between the \i{character set} understood by the server and
1222 the character set understood by PuTTY.
1224 \S{config-charset} Controlling character set translation
1226 \cfg{winhelp-topic}{translation.codepage}
1228 During an interactive session, PuTTY receives a stream of 8-bit
1229 bytes from the server, and in order to display them on the screen it
1230 needs to know what character set to interpret them in.
1232 There are a lot of character sets to choose from. The \q{Received
1233 data assumed to be in which character set} option lets you select
1234 one. By default PuTTY will attempt to choose a character set that is
1235 right for your \i{locale} as reported by Windows; if it gets it wrong,
1236 you can select a different one using this control.
1238 A few notable character sets are:
1240 \b The \i{ISO-8859} series are all standard character sets that include
1241 various accented characters appropriate for different sets of
1244 \b The \i{Win125x} series are defined by Microsoft, for similar
1245 purposes. In particular Win1252 is almost equivalent to ISO-8859-1,
1246 but contains a few extra characters such as matched quotes and the
1249 \b If you want the old IBM PC character set with block graphics and
1250 line-drawing characters, you can select \q{\i{CP437}}.
1252 \b PuTTY also supports \i{Unicode} mode, in which the data coming from
1253 the server is interpreted as being in the \i{UTF-8} encoding of Unicode.
1254 If you select \q{UTF-8} as a character set you can use this mode.
1255 Not all server-side applications will support it.
1257 If you need support for a numeric \i{code page} which is not listed in
1258 the drop-down list, such as code page 866, then you can try entering
1259 its name manually (\c{\i{CP866}} for example) in the list box. If the
1260 underlying version of Windows has the appropriate translation table
1261 installed, PuTTY will use it.
1263 \S{config-cjk-ambig-wide} \q{Treat \i{CJK} ambiguous characters as wide}
1265 \cfg{winhelp-topic}{translation.cjkambigwide}
1267 There are \I{East Asian Ambiguous characters}some Unicode characters
1268 whose \I{character width}width is not well-defined. In most contexts, such
1269 characters should be treated as single-width for the purposes of \I{wrapping,
1270 terminal}wrapping and so on; however, in some CJK contexts, they are better
1271 treated as double-width for historical reasons, and some server-side
1272 applications may expect them to be displayed as such. Setting this option
1273 will cause PuTTY to take the double-width interpretation.
1275 If you use legacy CJK applications, and you find your lines are
1276 wrapping in the wrong places, or you are having other display
1277 problems, you might want to play with this setting.
1279 This option only has any effect in \i{UTF-8} mode (see \k{config-charset}).
1281 \S{config-cyr} \q{\i{Caps Lock} acts as \i{Cyrillic} switch}
1283 \cfg{winhelp-topic}{translation.cyrillic}
1285 This feature allows you to switch between a US/UK keyboard layout
1286 and a Cyrillic keyboard layout by using the Caps Lock key, if you
1287 need to type (for example) \i{Russian} and English side by side in the
1290 Currently this feature is not expected to work properly if your
1291 native keyboard layout is not US or UK.
1293 \S{config-linedraw} Controlling display of \i{line-drawing characters}
1295 \cfg{winhelp-topic}{translation.linedraw}
1297 VT100-series terminals allow the server to send \i{control sequence}s that
1298 shift temporarily into a separate character set for drawing simple
1299 lines and boxes. However, there are a variety of ways in which PuTTY
1300 can attempt to find appropriate characters, and the right one to use
1301 depends on the locally configured \i{font}. In general you should probably
1302 try lots of options until you find one that your particular font
1305 \b \q{Use Unicode line drawing code points} tries to use the box
1306 characters that are present in \i{Unicode}. For good Unicode-supporting
1307 fonts this is probably the most reliable and functional option.
1309 \b \q{Poor man's line drawing} assumes that the font \e{cannot}
1310 generate the line and box characters at all, so it will use the
1311 \c{+}, \c{-} and \c{|} characters to draw approximations to boxes.
1312 You should use this option if none of the other options works.
1314 \b \q{Font has XWindows encoding} is for use with fonts that have a
1315 special encoding, where the lowest 32 character positions (below the
1316 ASCII printable range) contain the line-drawing characters. This is
1317 unlikely to be the case with any standard Windows font; it will
1318 probably only apply to custom-built fonts or fonts that have been
1319 automatically converted from the X Window System.
1321 \b \q{Use font in both ANSI and OEM modes} tries to use the same
1322 font in two different character sets, to obtain a wider range of
1323 characters. This doesn't always work; some fonts claim to be a
1324 different size depending on which character set you try to use.
1326 \b \q{Use font in OEM mode only} is more reliable than that, but can
1327 miss out other characters from the main character set.
1329 \S{config-linedrawpaste} Controlling \i{copy and paste} of line drawing
1332 \cfg{winhelp-topic}{selection.linedraw}
1334 By default, when you copy and paste a piece of the PuTTY screen that
1335 contains VT100 line and box drawing characters, PuTTY will paste
1336 them in the form they appear on the screen: either \i{Unicode} line
1337 drawing code points, or the \q{poor man's} line-drawing characters
1338 \c{+}, \c{-} and \c{|}. The checkbox \q{Copy and paste VT100 line
1339 drawing chars as lqqqk} disables this feature, so line-drawing
1340 characters will be pasted as the \i{ASCII} characters that were printed
1341 to produce them. This will typically mean they come out mostly as
1342 \c{q} and \c{x}, with a scattering of \c{jklmntuvw} at the corners.
1343 This might be useful if you were trying to recreate the same box
1344 layout in another program, for example.
1346 Note that this option only applies to line-drawing characters which
1347 \e{were} printed by using the VT100 mechanism. Line-drawing
1348 characters that were received as Unicode code points will paste as
1351 \H{config-selection} The Selection panel
1353 The Selection panel allows you to control the way \i{copy and paste}
1354 work in the PuTTY window.
1356 \S{config-rtfpaste} Pasting in \i{Rich Text Format}
1358 \cfg{winhelp-topic}{selection.rtf}
1360 If you enable \q{Paste to clipboard in RTF as well as plain text},
1361 PuTTY will write formatting information to the clipboard as well as
1362 the actual text you copy. The effect of this is
1363 that if you paste into (say) a word processor, the text will appear
1364 in the word processor in the same \i{font}, \i{colour}, and style
1365 (e.g. bold, underline) PuTTY was using to display it.
1367 This option can easily be inconvenient, so by default it is
1370 \S{config-mouse} Changing the actions of the mouse buttons
1372 \cfg{winhelp-topic}{selection.buttons}
1374 PuTTY's copy and paste mechanism is by default modelled on the Unix
1375 \c{xterm} application. The X Window System uses a three-button mouse,
1376 and the convention is that the \i{left button} \I{selecting text}selects,
1377 the \i{right button} extends an existing selection, and the
1378 \i{middle button} pastes.
1380 Windows often only has two mouse buttons, so in PuTTY's default
1381 configuration (\q{Compromise}), the \e{right} button pastes, and the
1382 \e{middle} button (if you have one) \I{adjusting a selection}extends
1385 If you have a \i{three-button mouse} and you are already used to the
1386 \c{xterm} arrangement, you can select it using the \q{Action of
1387 mouse buttons} control.
1389 Alternatively, with the \q{Windows} option selected, the middle
1390 button extends, and the right button brings up a \i{context menu} (on
1391 which one of the options is \q{Paste}). (This context menu is always
1392 available by holding down Ctrl and right-clicking, regardless of the
1393 setting of this option.)
1395 \S{config-mouseshift} \q{Shift overrides application's use of mouse}
1397 \cfg{winhelp-topic}{selection.shiftdrag}
1399 PuTTY allows the server to send \i{control codes} that let it
1400 \I{mouse reporting}take over the mouse and use it for purposes other
1401 than \i{copy and paste}.
1402 Applications which use this feature include the text-mode web
1403 browser \c{links}, the Usenet newsreader \c{trn} version 4, and the
1404 file manager \c{mc} (Midnight Commander).
1406 When running one of these applications, pressing the mouse buttons
1407 no longer performs copy and paste. If you do need to copy and paste,
1408 you can still do so if you hold down Shift while you do your mouse
1411 However, it is possible in theory for applications to even detect
1412 and make use of Shift + mouse clicks. We don't know of any
1413 applications that do this, but in case someone ever writes one,
1414 unchecking the \q{Shift overrides application's use of mouse}
1415 checkbox will cause Shift + mouse clicks to go to the server as well
1416 (so that mouse-driven copy and paste will be completely disabled).
1418 If you want to prevent the application from taking over the mouse at
1419 all, you can do this using the Features control panel; see
1420 \k{config-features-mouse}.
1422 \S{config-rectselect} Default selection mode
1424 \cfg{winhelp-topic}{selection.rect}
1426 As described in \k{using-selection}, PuTTY has two modes of
1427 selecting text to be copied to the clipboard. In the default mode
1428 (\q{Normal}), dragging the mouse from point A to point B selects to
1429 the end of the line containing A, all the lines in between, and from
1430 the very beginning of the line containing B. In the other mode
1431 (\q{Rectangular block}), dragging the mouse between two points
1432 defines a rectangle, and everything within that rectangle is copied.
1434 Normally, you have to hold down Alt while dragging the mouse to
1435 select a rectangular block. Using the \q{Default selection mode}
1436 control, you can set \i{rectangular selection} as the default, and then
1437 you have to hold down Alt to get the \e{normal} behaviour.
1439 \S{config-charclasses} Configuring \i{word-by-word selection}
1441 \cfg{winhelp-topic}{selection.charclasses}
1443 PuTTY will select a word at a time in the terminal window if you
1444 \i{double-click} to begin the drag. This panel allows you to control
1445 precisely what is considered to be a word.
1447 Each character is given a \e{class}, which is a small number
1448 (typically 0, 1 or 2). PuTTY considers a single word to be any
1449 number of adjacent characters in the same class. So by modifying the
1450 assignment of characters to classes, you can modify the word-by-word
1451 selection behaviour.
1453 In the default configuration, the \i{character classes} are:
1455 \b Class 0 contains \i{white space} and control characters.
1457 \b Class 1 contains most \i{punctuation}.
1459 \b Class 2 contains letters, numbers and a few pieces of punctuation
1460 (the double quote, minus sign, period, forward slash and
1463 So, for example, if you assign the \c{@} symbol into character class
1464 2, you will be able to select an e-mail address with just a double
1467 In order to adjust these assignments, you start by selecting a group
1468 of characters in the list box. Then enter a class number in the edit
1469 box below, and press the \q{Set} button.
1471 This mechanism currently only covers ASCII characters, because it
1472 isn't feasible to expand the list to cover the whole of Unicode.
1474 Character class definitions can be modified by \i{control sequence}s
1475 sent by the server. This configuration option controls the
1476 \e{default} state, which will be restored when you reset the
1477 terminal (see \k{reset-terminal}). However, if you modify this
1478 option in mid-session using \q{Change Settings}, it will take effect
1481 \H{config-colours} The Colours panel
1483 The Colours panel allows you to control PuTTY's use of \i{colour}.
1485 \S{config-ansicolour} \q{Allow terminal to specify \i{ANSI colours}}
1487 \cfg{winhelp-topic}{colours.ansi}
1489 This option is enabled by default. If it is disabled, PuTTY will
1490 ignore any \i{control sequence}s sent by the server to request coloured
1493 If you have a particularly garish application, you might want to
1494 turn this option off and make PuTTY only use the default foreground
1495 and background colours.
1497 \S{config-xtermcolour} \q{Allow terminal to use xterm \i{256-colour mode}}
1499 \cfg{winhelp-topic}{colours.xterm256}
1501 This option is enabled by default. If it is disabled, PuTTY will
1502 ignore any control sequences sent by the server which use the
1503 extended 256-colour mode supported by recent versions of \cw{xterm}.
1505 If you have an application which is supposed to use 256-colour mode
1506 and it isn't working, you may find you need to tell your server that
1507 your terminal supports 256 colours. On Unix, you do this by ensuring
1508 that the setting of \i\cw{TERM} describes a 256-colour-capable
1509 terminal. You can check this using a command such as \c{infocmp}:
1511 \c $ infocmp | grep colors
1512 \c colors#256, cols#80, it#8, lines#24, pairs#256,
1515 If you do not see \cq{colors#256} in the output, you may need to
1516 change your terminal setting. On modern Linux machines, you could
1517 try \cq{xterm-256color}.
1519 \S{config-boldcolour} \q{Bolded text is a different colour}
1521 \cfg{winhelp-topic}{colours.bold}
1523 When the server sends a \i{control sequence} indicating that some text
1524 should be displayed in \i{bold}, PuTTY can handle this two ways. It can
1525 either change the \i{font} for a bold version, or use the same font in a
1526 brighter colour. This control lets you choose which.
1528 By default the box is checked, so non-bold text is displayed in
1529 light grey and bold text is displayed in bright white (and similarly
1530 in other colours). If you uncheck the box, bold and non-bold text
1531 will be displayed in the same colour, and instead the font will
1532 change to indicate the difference.
1534 \S{config-logpalette} \q{Attempt to use \i{logical palettes}}
1536 \cfg{winhelp-topic}{colours.logpal}
1538 Logical palettes are a mechanism by which a Windows application
1539 running on an \i{8-bit colour} display can select precisely the colours
1540 it wants instead of going with the Windows standard defaults.
1542 If you are not getting the colours you ask for on an 8-bit display,
1543 you can try enabling this option. However, be warned that it's never
1546 \S{config-syscolour} \q{Use \i{system colours}}
1548 \cfg{winhelp-topic}{colours.system}
1550 Enabling this option will cause PuTTY to ignore the configured colours
1551 for \I{default background}\I{default foreground}\q{Default
1552 Background/Foreground} and \I{cursor colour}\q{Cursor Colour/Text} (see
1553 \k{config-colourcfg}), instead going with the system-wide defaults.
1555 Note that non-bold and \i{bold text} will be the same colour if this
1556 option is enabled. You might want to change to indicating bold text
1557 by font changes (see \k{config-boldcolour}).
1559 \S{config-colourcfg} Adjusting the colours in the \i{terminal window}
1561 \cfg{winhelp-topic}{colours.config}
1563 The main colour control allows you to specify exactly what colours
1564 things should be displayed in. To modify one of the PuTTY colours,
1565 use the list box to select which colour you want to modify. The \i{RGB
1566 values} for that colour will appear on the right-hand side of the
1567 list box. Now, if you press the \q{Modify} button, you will be
1568 presented with a colour selector, in which you can choose a new
1569 colour to go in place of the old one. (You may also edit the RGB
1570 values directly in the edit boxes, if you wish; each value is an
1571 integer from 0 to 255.)
1573 PuTTY allows you to set the \i{cursor colour}, the \i{default foreground}
1574 and \I{default background}background, and the precise shades of all the
1575 \I{ANSI colours}ANSI configurable colours (black, red, green, yellow, blue,
1576 magenta, cyan, and white). You can also modify the precise shades used for
1577 the \i{bold} versions of these colours; these are used to display bold text
1578 if you have selected \q{Bolded text is a different colour}, and can also be
1579 used if the server asks specifically to use them. (Note that \q{Default
1580 Bold Background} is \e{not} the background colour used for bold text;
1581 it is only used if the server specifically asks for a bold
1584 \H{config-connection} The Connection panel
1586 The Connection panel allows you to configure options that apply to
1587 more than one type of \i{connection}.
1589 \S{config-keepalive} Using \i{keepalives} to prevent disconnection
1591 \cfg{winhelp-topic}{connection.keepalive}
1593 If you find your sessions are closing unexpectedly (most often with
1594 \q{Connection reset by peer}) after they have been idle for a while,
1595 you might want to try using this option.
1597 Some network \i{routers} and \i{firewalls} need to keep track of all
1598 connections through them. Usually, these firewalls will assume a
1599 connection is dead if no data is transferred in either direction
1600 after a certain time interval. This can cause PuTTY sessions to be
1601 unexpectedly closed by the firewall if no traffic is seen in the
1602 session for some time.
1604 The keepalive option (\q{Seconds between keepalives}) allows you to
1605 configure PuTTY to send data through the session at regular
1606 intervals, in a way that does not disrupt the actual terminal
1607 session. If you find your firewall is cutting \i{idle connections} off,
1608 you can try entering a non-zero value in this field. The value is
1609 measured in seconds; so, for example, if your firewall cuts
1610 connections off after ten minutes then you might want to enter 300
1611 seconds (5 minutes) in the box.
1613 Note that keepalives are not always helpful. They help if you have a
1614 firewall which drops your connection after an idle period; but if
1615 the network between you and the server suffers from \i{breaks in
1616 connectivity} then keepalives can actually make things worse. If a
1617 session is idle, and connectivity is temporarily lost between the
1618 endpoints, but the connectivity is restored before either side tries
1619 to send anything, then there will be no problem - neither endpoint
1620 will notice that anything was wrong. However, if one side does send
1621 something during the break, it will repeatedly try to re-send, and
1622 eventually give up and abandon the connection. Then when
1623 connectivity is restored, the other side will find that the first
1624 side doesn't believe there is an open connection any more.
1625 Keepalives can make this sort of problem worse, because they
1626 increase the probability that PuTTY will attempt to send data during
1627 a break in connectivity. (Other types of periodic network activity
1628 can cause this behaviour; in particular, SSH-2 re-keys can have
1629 this effect. See \k{config-ssh-kex-rekey}.)
1631 Therefore, you might find that keepalives help
1632 connection loss, or you might find they make it worse, depending on
1633 what \e{kind} of network problems you have between you and the
1636 Keepalives are only supported in Telnet and SSH; the Rlogin and Raw
1637 protocols offer no way of implementing them. (For an alternative, see
1638 \k{config-tcp-keepalives}.)
1640 Note that if you are using \i{SSH-1} and the server has a bug that makes
1641 it unable to deal with SSH-1 ignore messages (see
1642 \k{config-ssh-bug-ignore1}), enabling keepalives will have no effect.
1644 \S{config-nodelay} \q{Disable \i{Nagle's algorithm}}
1646 \cfg{winhelp-topic}{connection.nodelay}
1648 Nagle's algorithm is a detail of TCP/IP implementations that tries
1649 to minimise the number of small data packets sent down a network
1650 connection. With Nagle's algorithm enabled, PuTTY's \i{bandwidth} usage
1651 will be slightly more efficient; with it disabled, you may find you
1652 get a faster response to your keystrokes when connecting to some
1655 The Nagle algorithm is disabled by default for \i{interactive connections}.
1657 \S{config-tcp-keepalives} \q{Enable \i{TCP keepalives}}
1659 \cfg{winhelp-topic}{connection.tcpkeepalive}
1661 \e{NOTE:} TCP keepalives should not be confused with the
1662 application-level keepalives described in \k{config-keepalive}. If in
1663 doubt, you probably want application-level keepalives; TCP keepalives
1664 are provided for completeness.
1666 The idea of TCP keepalives is similar to application-level keepalives,
1667 and the same caveats apply. The main differences are:
1669 \b TCP keepalives are available on \e{all} connection types, including
1672 \b The interval between TCP keepalives is usually much longer,
1673 typically two hours; this is set by the operating system, and cannot
1674 be configured within PuTTY.
1676 \b If the operating system does not receive a response to a keepalive,
1677 it may send out more in quick succession and terminate the connection
1678 if no response is received.
1680 TCP keepalives may be more useful for ensuring that \i{half-open connections}
1681 are terminated than for keeping a connection alive.
1683 TCP keepalives are disabled by default.
1685 \S{config-address-family} \I{Internet protocol version}\q{Internet protocol}
1687 \cfg{winhelp-topic}{connection.ipversion}
1689 This option allows the user to select between the old and new
1690 Internet protocols and addressing schemes (\i{IPv4} and \i{IPv6}). The
1691 default setting is \q{Auto}, which means PuTTY will do something
1692 sensible and try to guess which protocol you wanted. (If you specify
1693 a literal \i{Internet address}, it will use whichever protocol that
1694 address implies. If you provide a \i{hostname}, it will see what kinds
1695 of address exist for that hostname; it will use IPv6 if there is an
1696 IPv6 address available, and fall back to IPv4 if not.)
1698 If you need to force PuTTY to use a particular protocol, you can
1699 explicitly set this to \q{IPv4} or \q{IPv6}.
1701 \H{config-data} The Data panel
1703 The Data panel allows you to configure various pieces of data which
1704 can be sent to the server to affect your connection at the far end.
1706 Each option on this panel applies to more than one protocol.
1707 Options which apply to only one protocol appear on that protocol's
1708 configuration panels.
1710 \S{config-username} \q{\ii{Auto-login username}}
1712 \cfg{winhelp-topic}{connection.username}
1714 All three of the SSH, Telnet and Rlogin protocols allow you to
1715 specify what user name you want to log in as, without having to type
1716 it explicitly every time. (Some Telnet servers don't support this.)
1718 In this box you can type that user name.
1720 \S{config-termtype} \q{\ii{Terminal-type} string}
1722 \cfg{winhelp-topic}{connection.termtype}
1724 Most servers you might connect to with PuTTY are designed to be
1725 connected to from lots of different types of terminal. In order to
1726 send the right \i{control sequence}s to each one, the server will need
1727 to know what type of terminal it is dealing with. Therefore, each of
1728 the SSH, Telnet and Rlogin protocols allow a text string to be sent
1729 down the connection describing the terminal. On a \i{Unix} server,
1730 this selects an entry from the \i\c{termcap} or \i\c{terminfo} database
1731 that tells applications what \i{control sequences} to send to the
1732 terminal, and what character sequences to expect the \i{keyboard}
1735 PuTTY attempts to emulate the Unix \i\c{xterm} program, and by default
1736 it reflects this by sending \c{xterm} as a terminal-type string. If
1737 you find this is not doing what you want - perhaps the remote
1738 system reports \q{Unknown terminal type} - you could try setting
1739 this to something different, such as \i\c{vt220}.
1741 If you're not sure whether a problem is due to the terminal type
1742 setting or not, you probably need to consult the manual for your
1743 application or your server.
1745 \S{config-termspeed} \q{\ii{Terminal speed}s}
1747 \cfg{winhelp-topic}{connection.termspeed}
1749 The Telnet, Rlogin, and SSH protocols allow the client to specify
1750 terminal speeds to the server.
1752 This parameter does \e{not} affect the actual speed of the connection,
1753 which is always \q{as fast as possible}; it is just a hint that is
1754 sometimes used by server software to modify its behaviour. For
1755 instance, if a slow speed is indicated, the server may switch to a
1756 less \i{bandwidth}-hungry display mode.
1758 The value is usually meaningless in a network environment, but
1759 PuTTY lets you configure it, in case you find the server is reacting
1760 badly to the default value.
1762 The format is a pair of numbers separated by a comma, for instance,
1763 \c{38400,38400}. The first number represents the output speed
1764 (\e{from} the server) in bits per second, and the second is the input
1765 speed (\e{to} the server). (Only the first is used in the Rlogin
1768 This option has no effect on Raw connections.
1770 \S{config-environ} Setting \i{environment variables} on the server
1772 \cfg{winhelp-topic}{telnet.environ}
1774 The Telnet protocol provides a means for the client to pass
1775 environment variables to the server. Many Telnet servers have
1776 stopped supporting this feature due to security flaws, but PuTTY
1777 still supports it for the benefit of any servers which have found
1778 other ways around the security problems than just disabling the
1781 Version 2 of the SSH protocol also provides a similar mechanism,
1782 which is easier to implement without security flaws. Newer \i{SSH-2}
1783 servers are more likely to support it than older ones.
1785 This configuration data is not used in the SSH-1, rlogin or raw
1788 To add an environment variable to the list transmitted down the
1789 connection, you enter the variable name in the \q{Variable} box,
1790 enter its value in the \q{Value} box, and press the \q{Add} button.
1791 To remove one from the list, select it in the list box and press
1794 \H{config-proxy} The Proxy panel
1796 \cfg{winhelp-topic}{proxy.main}
1798 The \ii{Proxy} panel allows you to configure PuTTY to use various types
1799 of proxy in order to make its network connections. The settings in
1800 this panel affect the primary network connection forming your PuTTY
1801 session, and also any extra connections made as a result of SSH \i{port
1802 forwarding} (see \k{using-port-forwarding}).
1804 \S{config-proxy-type} Setting the proxy type
1806 \cfg{winhelp-topic}{proxy.type}
1808 The \q{Proxy type} radio buttons allow you to configure what type of
1809 proxy you want PuTTY to use for its network connections. The default
1810 setting is \q{None}; in this mode no proxy is used for any
1813 \b Selecting \I{HTTP proxy}\q{HTTP} allows you to proxy your connections
1814 through a web server supporting the HTTP \cw{CONNECT} command, as documented
1815 in \W{http://www.ietf.org/rfc/rfc2817.txt}{RFC 2817}.
1817 \b Selecting \q{SOCKS 4} or \q{SOCKS 5} allows you to proxy your
1818 connections through a \i{SOCKS server}.
1820 \b Many firewalls implement a less formal type of proxy in which a
1821 user can make a Telnet connection directly to the firewall machine
1822 and enter a command such as \c{connect myhost.com 22} to connect
1823 through to an external host. Selecting \I{Telnet proxy}\q{Telnet}
1824 allows you to tell PuTTY to use this type of proxy.
1826 \b Selecting \I{Local proxy}\q{Local} allows you to specify an arbitrary
1827 command on the local machine to act as a proxy. When the session is
1828 started, instead of creating a TCP connection, PuTTY runs the command
1829 (specified in \k{config-proxy-command}), and uses its standard input and
1833 This could be used, for instance, to talk to some kind of network proxy
1834 that PuTTY does not natively support; or you could tunnel a connection
1835 over something other than TCP/IP entirely.
1837 If you want your local proxy command to make a secondary SSH
1838 connection to a proxy host and then tunnel the primary connection
1839 over that, you might well want the \c{-nc} command-line option in
1840 Plink. See \k{using-cmdline-ncmode} for more information.
1843 \S{config-proxy-exclude} Excluding parts of the network from proxying
1845 \cfg{winhelp-topic}{proxy.exclude}
1847 Typically you will only need to use a proxy to connect to non-local
1848 parts of your network; for example, your proxy might be required for
1849 connections outside your company's internal network. In the
1850 \q{Exclude Hosts/IPs} box you can enter ranges of IP addresses, or
1851 ranges of DNS names, for which PuTTY will avoid using the proxy and
1852 make a direct connection instead.
1854 The \q{Exclude Hosts/IPs} box may contain more than one exclusion
1855 range, separated by commas. Each range can be an IP address or a DNS
1856 name, with a \c{*} character allowing wildcards. For example:
1860 This excludes any host with a name ending in \c{.example.com} from
1865 This excludes any host with an IP address starting with 192.168.88
1868 \c 192.168.88.*,*.example.com
1870 This excludes both of the above ranges at once.
1872 Connections to the local host (the host name \i\c{localhost}, and any
1873 \i{loopback IP address}) are never proxied, even if the proxy exclude
1874 list does not explicitly contain them. It is very unlikely that this
1875 behaviour would ever cause problems, but if it does you can change
1876 it by enabling \q{Consider proxying local host connections}.
1878 Note that if you are doing \I{proxy DNS}DNS at the proxy (see
1879 \k{config-proxy-dns}), you should make sure that your proxy
1880 exclusion settings do not depend on knowing the IP address of a
1881 host. If the name is passed on to the proxy without PuTTY looking it
1882 up, it will never know the IP address and cannot check it against
1885 \S{config-proxy-dns} \I{proxy DNS}\ii{Name resolution} when using a proxy
1887 \cfg{winhelp-topic}{proxy.dns}
1889 If you are using a proxy to access a private network, it can make a
1890 difference whether \i{DNS} name resolution is performed by PuTTY itself
1891 (on the client machine) or performed by the proxy.
1893 The \q{Do DNS name lookup at proxy end} configuration option allows
1894 you to control this. If you set it to \q{No}, PuTTY will always do
1895 its own DNS, and will always pass an IP address to the proxy. If you
1896 set it to \q{Yes}, PuTTY will always pass host names straight to the
1897 proxy without trying to look them up first.
1899 If you set this option to \q{Auto} (the default), PuTTY will do
1900 something it considers appropriate for each type of proxy. Telnet,
1901 HTTP, and SOCKS5 proxies will have host names passed straight to
1902 them; SOCKS4 proxies will not.
1904 Note that if you are doing DNS at the proxy, you should make sure
1905 that your proxy exclusion settings (see \k{config-proxy-exclude}) do
1906 not depend on knowing the IP address of a host. If the name is
1907 passed on to the proxy without PuTTY looking it up, it will never
1908 know the IP address and cannot check it against your list.
1910 The original SOCKS 4 protocol does not support proxy-side DNS. There
1911 is a protocol extension (SOCKS 4A) which does support it, but not
1912 all SOCKS 4 servers provide this extension. If you enable proxy DNS
1913 and your SOCKS 4 server cannot deal with it, this might be why.
1915 \S{config-proxy-auth} \I{proxy username}Username and \I{proxy password}password
1917 \cfg{winhelp-topic}{proxy.auth}
1919 If your proxy requires \I{proxy authentication}authentication, you can
1920 enter a username and a password in the \q{Username} and \q{Password} boxes.
1922 \I{security hazard}Note that if you save your session, the proxy
1923 password will be saved in plain text, so anyone who can access your PuTTY
1924 configuration data will be able to discover it.
1926 Authentication is not fully supported for all forms of proxy:
1928 \b Username and password authentication is supported for HTTP
1929 proxies and SOCKS 5 proxies.
1933 \b With SOCKS 5, authentication is via \i{CHAP} if the proxy
1934 supports it (this is not supported in \i{PuTTYtel}); otherwise the
1935 password is sent to the proxy in \I{plaintext password}plain text.
1937 \b With HTTP proxying, the only currently supported authentication
1938 method is \I{HTTP basic}\q{basic}, where the password is sent to the proxy
1939 in \I{plaintext password}plain text.
1943 \b SOCKS 4 can use the \q{Username} field, but does not support
1946 \b You can specify a way to include a username and password in the
1947 Telnet/Local proxy command (see \k{config-proxy-command}).
1949 \S{config-proxy-command} Specifying the Telnet or Local proxy command
1951 \cfg{winhelp-topic}{proxy.command}
1953 If you are using the \i{Telnet proxy} type, the usual command required
1954 by the firewall's Telnet server is \c{connect}, followed by a host
1955 name and a port number. If your proxy needs a different command,
1956 you can enter an alternative here.
1958 If you are using the \i{Local proxy} type, the local command to run
1961 In this string, you can use \c{\\n} to represent a new-line, \c{\\r}
1962 to represent a carriage return, \c{\\t} to represent a tab
1963 character, and \c{\\x} followed by two hex digits to represent any
1964 other character. \c{\\\\} is used to encode the \c{\\} character
1967 Also, the special strings \c{%host} and \c{%port} will be replaced
1968 by the host name and port number you want to connect to. The strings
1969 \c{%user} and \c{%pass} will be replaced by the proxy username and
1970 password you specify. The strings \c{%proxyhost} and \c{%proxyport}
1971 will be replaced by the host details specified on the \e{Proxy} panel,
1972 if any (this is most likely to be useful for the Local proxy type).
1973 To get a literal \c{%} sign, enter \c{%%}.
1975 If a Telnet proxy server prompts for a username and password
1976 before commands can be sent, you can use a command such as:
1978 \c %user\n%pass\nconnect %host %port\n
1980 This will send your username and password as the first two lines to
1981 the proxy, followed by a command to connect to the desired host and
1982 port. Note that if you do not include the \c{%user} or \c{%pass}
1983 tokens in the Telnet command, then the \q{Username} and \q{Password}
1984 configuration fields will be ignored.
1986 \H{config-telnet} The \i{Telnet} panel
1988 The Telnet panel allows you to configure options that only apply to
1991 \S{config-oldenviron} \q{Handling of OLD_ENVIRON ambiguity}
1993 \cfg{winhelp-topic}{telnet.oldenviron}
1995 The original Telnet mechanism for passing \i{environment variables} was
1996 badly specified. At the time the standard (RFC 1408) was written,
1997 BSD telnet implementations were already supporting the feature, and
1998 the intention of the standard was to describe the behaviour the BSD
1999 implementations were already using.
2001 Sadly there was a typing error in the standard when it was issued,
2002 and two vital function codes were specified the wrong way round. BSD
2003 implementations did not change, and the standard was not corrected.
2004 Therefore, it's possible you might find either \i{BSD} or \i{RFC}-compliant
2005 implementations out there. This switch allows you to choose which
2006 one PuTTY claims to be.
2008 The problem was solved by issuing a second standard, defining a new
2009 Telnet mechanism called \i\cw{NEW_ENVIRON}, which behaved exactly like
2010 the original \i\cw{OLD_ENVIRON} but was not encumbered by existing
2011 implementations. Most Telnet servers now support this, and it's
2012 unambiguous. This feature should only be needed if you have trouble
2013 passing environment variables to quite an old server.
2015 \S{config-ptelnet} Passive and active \i{Telnet negotiation} modes
2017 \cfg{winhelp-topic}{telnet.passive}
2019 In a Telnet connection, there are two types of data passed between
2020 the client and the server: actual text, and \e{negotiations} about
2021 which Telnet extra features to use.
2023 PuTTY can use two different strategies for negotiation:
2025 \b In \I{active Telnet negotiation}\e{active} mode, PuTTY starts to send
2026 negotiations as soon as the connection is opened.
2028 \b In \I{passive Telnet negotiation}\e{passive} mode, PuTTY will wait to
2029 negotiate until it sees a negotiation from the server.
2031 The obvious disadvantage of passive mode is that if the server is
2032 also operating in a passive mode, then negotiation will never begin
2033 at all. For this reason PuTTY defaults to active mode.
2035 However, sometimes passive mode is required in order to successfully
2036 get through certain types of firewall and \i{Telnet proxy} server. If
2037 you have confusing trouble with a \i{firewall}, you could try enabling
2038 passive mode to see if it helps.
2040 \S{config-telnetkey} \q{Keyboard sends \i{Telnet special commands}}
2042 \cfg{winhelp-topic}{telnet.specialkeys}
2044 If this box is checked, several key sequences will have their normal
2047 \b the Backspace key on the keyboard will send the \I{Erase Character,
2048 Telnet special command}Telnet special backspace code;
2050 \b Control-C will send the Telnet special \I{Interrupt Process, Telnet
2051 special command}Interrupt Process code;
2053 \b Control-Z will send the Telnet special \I{Suspend Process, Telnet
2054 special command}Suspend Process code.
2056 You probably shouldn't enable this
2057 unless you know what you're doing.
2059 \S{config-telnetnl} \q{Return key sends \i{Telnet New Line} instead of ^M}
2061 \cfg{winhelp-topic}{telnet.newline}
2063 Unlike most other remote login protocols, the Telnet protocol has a
2064 special \q{\i{new line}} code that is not the same as the usual line
2065 endings of Control-M or Control-J. By default, PuTTY sends the
2066 Telnet New Line code when you press Return, instead of sending
2067 Control-M as it does in most other protocols.
2069 Most Unix-style Telnet servers don't mind whether they receive
2070 Telnet New Line or Control-M; some servers do expect New Line, and
2071 some servers prefer to see ^M. If you are seeing surprising
2072 behaviour when you press Return in a Telnet session, you might try
2073 turning this option off to see if it helps.
2075 \H{config-rlogin} The Rlogin panel
2077 The \i{Rlogin} panel allows you to configure options that only apply to
2080 \S{config-rlogin-localuser} \I{local username in Rlogin}\q{Local username}
2082 \cfg{winhelp-topic}{rlogin.localuser}
2084 Rlogin allows an automated (password-free) form of login by means of
2085 a file called \i\c{.rhosts} on the server. You put a line in your
2086 \c{.rhosts} file saying something like \c{jbloggs@pc1.example.com},
2087 and then when you make an Rlogin connection the client transmits the
2088 username of the user running the Rlogin client. The server checks
2089 the username and hostname against \c{.rhosts}, and if they match it
2090 \I{passwordless login}does not ask for a password.
2092 This only works because Unix systems contain a safeguard to stop a
2093 user from pretending to be another user in an Rlogin connection.
2094 Rlogin connections have to come from \I{privileged port}port numbers below
2095 1024, and Unix systems prohibit this to unprivileged processes; so when the
2096 server sees a connection from a low-numbered port, it assumes the
2097 client end of the connection is held by a privileged (and therefore
2098 trusted) process, so it believes the claim of who the user is.
2100 Windows does not have this restriction: \e{any} user can initiate an
2101 outgoing connection from a low-numbered port. Hence, the Rlogin
2102 \c{.rhosts} mechanism is completely useless for securely
2103 distinguishing several different users on a Windows machine. If you
2104 have a \c{.rhosts} entry pointing at a Windows PC, you should assume
2105 that \e{anyone} using that PC can \i{spoof} your username in
2106 an Rlogin connection and access your account on the server.
2108 The \q{Local username} control allows you to specify what user name
2109 PuTTY should claim you have, in case it doesn't match your \i{Windows
2110 user name} (or in case you didn't bother to set up a Windows user
2113 \H{config-ssh} The SSH panel
2115 The \i{SSH} panel allows you to configure options that only apply to
2118 \S{config-command} Executing a specific command on the server
2120 \cfg{winhelp-topic}{ssh.command}
2122 In SSH, you don't have to run a general shell session on the server.
2123 Instead, you can choose to run a single specific command (such as a
2124 mail user agent, for example). If you want to do this, enter the
2125 command in the \q{\ii{Remote command}} box.
2127 Note that most servers will close the session after executing the
2130 \S{config-ssh-noshell} \q{Don't start a \I{remote shell}shell or
2131 \I{remote command}command at all}
2133 \cfg{winhelp-topic}{ssh.noshell}
2135 If you tick this box, PuTTY will not attempt to run a shell or
2136 command after connecting to the remote server. You might want to use
2137 this option if you are only using the SSH connection for \i{port
2138 forwarding}, and your user account on the server does not have the
2139 ability to run a shell.
2141 This feature is only available in \i{SSH protocol version 2} (since the
2142 version 1 protocol assumes you will always want to run a shell).
2144 This feature can also be enabled using the \c{-N} command-line
2145 option; see \k{using-cmdline-noshell}.
2147 If you use this feature in Plink, you will not be able to terminate
2148 the Plink process by any graceful means; the only way to kill it
2149 will be by pressing Control-C or sending a kill signal from another
2152 \S{config-ssh-comp} \q{Enable \i{compression}}
2154 \cfg{winhelp-topic}{ssh.compress}
2156 This enables data compression in the SSH connection: data sent by
2157 the server is compressed before sending, and decompressed at the
2158 client end. Likewise, data sent by PuTTY to the server is compressed
2159 first and the server decompresses it at the other end. This can help
2160 make the most of a low-\i{bandwidth} connection.
2162 \S{config-ssh-prot} \q{Preferred \i{SSH protocol version}}
2164 \cfg{winhelp-topic}{ssh.protocol}
2166 This allows you to select whether you would like to use \i{SSH protocol
2167 version 1} or \I{SSH-2}version 2. \#{FIXME: say something about this elsewhere?}
2169 PuTTY will attempt to use protocol 1 if the server you connect to
2170 does not offer protocol 2, and vice versa.
2172 If you select \q{1 only} or \q{2 only} here, PuTTY will only connect
2173 if the server you connect to offers the SSH protocol version you
2176 \S{config-ssh-encryption} \ii{Encryption} algorithm selection
2178 \cfg{winhelp-topic}{ssh.ciphers}
2180 PuTTY supports a variety of different \i{encryption algorithm}s, and
2181 allows you to choose which one you prefer to use. You can do this by
2182 dragging the algorithms up and down in the list box (or moving them
2183 using the Up and Down buttons) to specify a preference order. When
2184 you make an SSH connection, PuTTY will search down the list from the
2185 top until it finds an algorithm supported by the server, and then
2188 PuTTY currently supports the following algorithms:
2190 \b \i{AES} (Rijndael) - 256, 192, or 128-bit SDCTR or CBC (SSH-2 only)
2192 \b \i{Arcfour} (RC4) - 256 or 128-bit stream cipher (SSH-2 only)
2194 \b \i{Blowfish} - 256-bit SDCTR (SSH-2 only) or 128-bit CBC
2196 \b \ii{Triple-DES} - 168-bit SDCTR (SSH-2 only) or CBC
2198 \b \ii{Single-DES} - 56-bit CBC (see below for SSH-2)
2200 If the algorithm PuTTY finds is below the \q{warn below here} line,
2201 you will see a warning box when you make the connection:
2203 \c The first cipher supported by the server
2204 \c is single-DES, which is below the configured
2205 \c warning threshold.
2206 \c Do you want to continue with this connection?
2208 This warns you that the first available encryption is not a very
2209 secure one. Typically you would put the \q{warn below here} line
2210 between the encryptions you consider secure and the ones you
2211 consider substandard. By default, PuTTY supplies a preference order
2212 intended to reflect a reasonable preference in terms of security and
2215 In SSH-2, the encryption algorithm is negotiated independently for
2216 each direction of the connection, although PuTTY does not support
2217 separate configuration of the preference orders. As a result you may
2218 get two warnings similar to the one above, possibly with different
2221 Single-DES is not recommended in the SSH-2 protocol
2222 standards, but one or two server implementations do support it.
2223 PuTTY can use single-DES to interoperate with
2224 these servers if you enable the \q{Enable legacy use of single-DES in
2225 SSH-2} option; by default this is disabled and PuTTY will stick to
2226 recommended ciphers.
2228 \H{config-ssh-kex} The Kex panel
2230 \# FIXME: This whole section is draft. Feel free to revise.
2232 The Kex panel (short for \q{\i{key exchange}}) allows you to configure
2233 options related to SSH-2 key exchange.
2235 Key exchange occurs at the start of an SSH connection (and
2236 occasionally thereafter); it establishes a \i{shared secret} that is used
2237 as the basis for all of SSH's security features. It is therefore very
2238 important for the security of the connection that the key exchange is
2241 Key exchange is a cryptographically intensive process; if either the
2242 client or the server is a relatively slow machine, the slower methods
2243 may take several tens of seconds to complete.
2245 If connection startup is too slow, or the connection hangs
2246 periodically, you may want to try changing these settings.
2248 If you don't understand what any of this means, it's safe to leave
2249 these settings alone.
2251 This entire panel is only relevant to SSH protocol version 2; none of
2252 these settings affect SSH-1 at all.
2254 \S{config-ssh-kex-order} \ii{Key exchange algorithm} selection
2256 \cfg{winhelp-topic}{ssh.kex.order}
2258 PuTTY supports a variety of SSH-2 key exchange methods, and allows you
2259 to choose which one you prefer to use; configuration is similar to
2260 cipher selection (see \k{config-ssh-encryption}).
2262 PuTTY currently supports the following varieties of \i{Diffie-Hellman key
2265 \b \q{Group 14}: a well-known 2048-bit group.
2267 \b \q{Group 1}: a well-known 1024-bit group. This is less secure
2268 \#{FIXME better words} than group 14, but may be faster with slow
2269 client or server machines, and may be the only method supported by
2270 older server software.
2272 \b \q{\ii{Group exchange}}: with this method, instead of using a fixed
2273 group, PuTTY requests that the server suggest a group to use for key
2274 exchange; the server can avoid groups known to be weak, and possibly
2275 invent new ones over time, without any changes required to PuTTY's
2276 configuration. We recommend use of this method, if possible.
2278 In addition, PuTTY supports \i{RSA key exchange}, which requires much less
2279 computational effort on the part of the client, and somewhat less on
2280 the part of the server, than Diffie-Hellman key exchange.
2282 If the first algorithm PuTTY finds is below the \q{warn below here}
2283 line, you will see a warning box when you make the connection, similar
2284 to that for cipher selection (see \k{config-ssh-encryption}).
2286 \S{config-ssh-kex-rekey} \ii{Repeat key exchange}
2288 \cfg{winhelp-topic}{ssh.kex.repeat}
2290 If the session key negotiated at connection startup is used too much
2291 or for too long, it may become feasible to mount attacks against the
2292 SSH connection. Therefore, the SSH-2 protocol specifies that a new key
2293 exchange should take place every so often; this can be initiated by
2294 either the client or the server.
2296 While this renegotiation is taking place, no data can pass through
2297 the SSH connection, so it may appear to \q{freeze}. (The occurrence of
2298 repeat key exchange is noted in the Event Log; see
2299 \k{using-eventlog}.) Usually the same algorithm is used as at the
2300 start of the connection, with a similar overhead.
2302 These options control how often PuTTY will initiate a repeat key
2303 exchange (\q{rekey}). You can also force a key exchange at any time
2304 from the Special Commands menu (see \k{using-specials}).
2306 \# FIXME: do we have any additions to the SSH-2 specs' advice on
2307 these values? Do we want to enforce any limits?
2309 \b \q{Max minutes before rekey} specifies the amount of time that is
2310 allowed to elapse before a rekey is initiated. If this is set to zero,
2311 PuTTY will not rekey due to elapsed time. The SSH-2 protocol
2312 specification recommends a timeout of at most 60 minutes.
2314 You might have a need to disable time-based rekeys completely for the same
2315 reasons that \i{keepalives} aren't always helpful. If you anticipate
2316 suffering a network dropout of several hours in the middle of an SSH
2317 connection, but were not actually planning to send \e{data} down
2318 that connection during those hours, then an attempted rekey in the
2319 middle of the dropout will probably cause the connection to be
2320 abandoned, whereas if rekeys are disabled then the connection should
2321 in principle survive (in the absence of interfering \i{firewalls}). See
2322 \k{config-keepalive} for more discussion of these issues; for these
2323 purposes, rekeys have much the same properties as keepalives.
2324 (Except that rekeys have cryptographic value in themselves, so you
2325 should bear that in mind when deciding whether to turn them off.)
2326 Note, however, the the SSH \e{server} can still initiate rekeys.
2328 \b \q{Max data before rekey} specifies the amount of data (in bytes)
2329 that is permitted to flow in either direction before a rekey is
2330 initiated. If this is set to zero, PuTTY will not rekey due to
2331 transferred data. The SSH-2 protocol specification recommends a limit
2332 of at most 1 gigabyte.
2336 As well as specifying a value in bytes, the following shorthand can be
2339 \b \cq{1k} specifies 1 kilobyte (1024 bytes).
2341 \b \cq{1M} specifies 1 megabyte (1024 kilobytes).
2343 \b \cq{1G} specifies 1 gigabyte (1024 megabytes).
2347 Disabling data-based rekeys entirely is a bad idea. The \i{integrity},
2348 and to a lesser extent, \i{confidentiality} of the SSH-2 protocol depend
2349 in part on rekeys occuring before a 32-bit packet sequence number
2350 wraps around. Unlike time-based rekeys, data-based rekeys won't occur
2351 when the SSH connection is idle, so they shouldn't cause the same
2352 problems. The SSH-1 protocol, incidentally, has even weaker integrity
2353 protection than SSH-2 without rekeys.
2355 \H{config-ssh-auth} The Auth panel
2357 The Auth panel allows you to configure \i{authentication} options for
2360 \S{config-ssh-noauth} \q{Bypass authentication entirely}
2362 \cfg{winhelp-topic}{ssh.auth.bypass}
2364 In SSH-2, it is possible to establish a connection without using SSH's
2365 mechanisms to identify or authenticate oneself to the server. Some
2366 servers may prefer to handle authentication in the data channel, for
2367 instance, or may simply require no authentication whatsoever.
2369 By default, PuTTY assumes the server requires authentication (most
2370 do), and thus must provide a username. If you find you are getting
2371 unwanted username prompts, you could try checking this option.
2373 This option only affects SSH-2 connections. SSH-1 connections always
2374 require an authentication step.
2376 \S{config-ssh-tryagent} \q{Attempt authentication using Pageant}
2378 \cfg{winhelp-topic}{ssh.auth.pageant}
2380 If this option is enabled, then PuTTY will look for Pageant (the SSH
2381 private-key storage agent) and attempt to authenticate with any
2382 suitable public keys Pageant currently holds.
2384 This behaviour is almost always desirable, and is therefore enabled
2385 by default. In rare cases you might need to turn it off in order to
2386 force authentication by some non-public-key method such as
2389 This option can also be controlled using the \c{-noagent}
2390 command-line option. See \k{using-cmdline-agentauth}.
2392 See \k{pageant} for more information about Pageant in general.
2394 \S{config-ssh-tis} \q{Attempt \I{TIS authentication}TIS or
2395 \i{CryptoCard authentication}}
2397 \cfg{winhelp-topic}{ssh.auth.tis}
2399 TIS and CryptoCard authentication are (despite their names) generic
2400 forms of simple \I{challenge/response authentication}challenge/response
2401 authentication available in SSH protocol version 1 only. You might use
2402 them if you were using \i{S/Key} \i{one-time passwords}, for example,
2403 or if you had a physical \i{security token} that generated responses
2404 to authentication challenges.
2406 With this switch enabled, PuTTY will attempt these forms of
2407 authentication if the server is willing to try them. You will be
2408 presented with a challenge string (which will be different every
2409 time) and must supply the correct response in order to log in. If
2410 your server supports this, you should talk to your system
2411 administrator about precisely what form these challenges and
2414 \S{config-ssh-ki} \q{Attempt \i{keyboard-interactive authentication}}
2416 \cfg{winhelp-topic}{ssh.auth.ki}
2418 The SSH-2 equivalent of TIS authentication is called
2419 \q{keyboard-interactive}. It is a flexible authentication method
2420 using an arbitrary sequence of requests and responses; so it is not
2421 only useful for \I{challenge/response authentication}challenge/response
2422 mechanisms such as \i{S/Key}, but it can also be used for (for example)
2423 asking the user for a \I{password expiry}new password when the old one
2426 PuTTY leaves this option enabled by default, but supplies a switch
2427 to turn it off in case you should have trouble with it.
2429 \S{config-ssh-agentfwd} \q{Allow \i{agent forwarding}}
2431 \cfg{winhelp-topic}{ssh.auth.agentfwd}
2433 This option allows the SSH server to open forwarded connections back
2434 to your local copy of \i{Pageant}. If you are not running Pageant, this
2435 option will do nothing.
2437 See \k{pageant} for general information on Pageant, and
2438 \k{pageant-forward} for information on agent forwarding. Note that
2439 there is a security risk involved with enabling this option; see
2440 \k{pageant-security} for details.
2442 \S{config-ssh-changeuser} \q{Allow attempted \i{changes of username} in SSH-2}
2444 \cfg{winhelp-topic}{ssh.auth.changeuser}
2446 In the SSH-1 protocol, it is impossible to change username after
2447 failing to authenticate. So if you mis-type your username at the
2448 PuTTY \q{login as:} prompt, you will not be able to change it except
2449 by restarting PuTTY.
2451 The SSH-2 protocol \e{does} allow changes of username, in principle,
2452 but does not make it mandatory for SSH-2 servers to accept them. In
2453 particular, \i{OpenSSH} does not accept a change of username; once you
2454 have sent one username, it will reject attempts to try to
2455 authenticate as another user. (Depending on the version of OpenSSH,
2456 it may quietly return failure for all login attempts, or it may send
2459 For this reason, PuTTY will by default not prompt you for your
2460 username more than once, in case the server complains. If you know
2461 your server can cope with it, you can enable the \q{Allow attempted
2462 changes of username} option to modify PuTTY's behaviour.
2464 \S{config-ssh-privkey} \q{\ii{Private key} file for authentication}
2466 \cfg{winhelp-topic}{ssh.auth.privkey}
2468 This box is where you enter the name of your private key file if you
2469 are using \i{public key authentication}. See \k{pubkey} for information
2470 about public key authentication in SSH.
2472 This key must be in PuTTY's native format (\c{*.\i{PPK}}). If you have a
2473 private key in another format that you want to use with PuTTY, see
2474 \k{puttygen-conversions}.
2476 If a key file is specified here, and \i{Pageant} is running (see
2477 \k{pageant}), PuTTY will first try asking Pageant to authenticate with
2478 that key, and ignore any other keys Pageant may have. If that fails,
2479 PuTTY will ask for a passphrase as normal.
2481 \H{config-ssh-tty} The TTY panel
2483 The TTY panel lets you configure the remote pseudo-terminal.
2485 \S{config-ssh-pty} \I{pseudo-terminal allocation}\q{Don't allocate
2488 \cfg{winhelp-topic}{ssh.nopty}
2490 When connecting to a \i{Unix} system, most \I{interactive
2491 connections}interactive shell sessions are run in a \e{pseudo-terminal},
2492 which allows the Unix system to pretend it's talking to a real physical
2493 terminal device but allows the SSH server to catch all the data coming
2494 from that fake device and send it back to the client.
2496 Occasionally you might find you have a need to run a session \e{not}
2497 in a pseudo-terminal. In PuTTY, this is generally only useful for
2498 very specialist purposes; although in Plink (see \k{plink}) it is
2499 the usual way of working.
2501 \S{config-ttymodes} Sending \i{terminal modes}
2503 \cfg{winhelp-topic}{ssh.ttymodes}
2505 The SSH protocol allows the client to send \q{terminal modes} for
2506 the remote pseudo-terminal. These usually control the server's
2507 expectation of the local terminal's behaviour.
2509 If your server does not have sensible defaults for these modes, you
2510 may find that changing them here helps. If you don't understand any of
2511 this, it's safe to leave these settings alone.
2513 (None of these settings will have any effect if no pseudo-terminal
2514 is requested or allocated.)
2516 You can add or modify a mode by selecting it from the drop-down list,
2517 choosing whether it's set automatically or to a specific value with
2518 the radio buttons and edit box, and hitting \q{Add}. A mode (or
2519 several) can be removed from the list by selecting them and hitting
2520 \q{Remove}. The effect of the mode list is as follows:
2522 \b If a mode is not on the list, it will not be specified to the
2523 server under any circumstances.
2525 \b If a mode is on the list:
2529 \b If the \q{Auto} option is selected, the PuTTY tools will decide
2530 whether to specify that mode to the server, and if so, will send
2535 PuTTY proper will send modes that it has an opinion on (currently only
2536 the code for the Backspace key, \cw{ERASE}). Plink on Unix
2537 will propagate appropriate modes from the local terminal, if any.
2541 \b If a value is specified, it will be sent to the server under all
2542 circumstances. The precise syntax of the value box depends on the
2547 By default, all of the available modes are listed as \q{Auto},
2548 which should do the right thing in most circumstances.
2550 The precise effect of each setting, if any, is up to the server. Their
2551 names come from \i{POSIX} and other Unix systems, and they are most
2552 likely to have a useful effect on such systems. (These are the same
2553 settings that can usually be changed using the \i\c{stty} command once
2554 logged in to such servers.)
2556 Some notable modes are described below; for fuller explanations, see
2557 your server documentation.
2559 \b \I{ERASE special character}\cw{ERASE} is the character that when typed
2560 by the user will delete one space to the left. When set to \q{Auto}
2561 (the default setting), this follows the setting of the local Backspace
2562 key in PuTTY (see \k{config-backspace}).
2565 This and other \i{special character}s are specified using \c{^C} notation
2566 for Ctrl-C, and so on. Use \c{^<27>} or \c{^<0x1B>} to specify a
2567 character numerically, and \c{^~} to get a literal \c{^}. Other
2568 non-control characters are denoted by themselves. Leaving the box
2569 entirely blank indicates that \e{no} character should be assigned to
2570 the specified function, although this may not be supported by all
2574 \b \I{QUIT special character}\cw{QUIT} is a special character that
2575 usually forcefully ends the current process on the server
2576 (\cw{SIGQUIT}). On many servers its default setting is Ctrl-backslash
2577 (\c{^\\}), which is easy to accidentally invoke on many keyboards. If
2578 this is getting in your way, you may want to change it to another
2579 character or turn it off entirely.
2581 \b Boolean modes such as \cw{ECHO} and \cw{ICANON} can be specified in
2582 PuTTY in a variety of ways, such as \cw{true}/\cw{false},
2583 \cw{yes}/\cw{no}, and \cw{0}/\cw{1}.
2585 \b Terminal speeds are configured elsewhere; see \k{config-termspeed}.
2587 \H{config-ssh-x11} The X11 panel
2589 \cfg{winhelp-topic}{ssh.tunnels.x11}
2591 The X11 panel allows you to configure \i{forwarding of X11} over an
2594 If your server lets you run X Window System applications, X11
2595 forwarding allows you to securely give those applications access to
2596 a local X display on your PC.
2598 To enable X11 forwarding, check the \q{Enable X11 forwarding} box.
2599 If your X display is somewhere unusual, you will need to enter its
2600 location in the \q{X display location} box; if this is left blank,
2601 PuTTY will try to find a sensible default in the environment, or use the
2602 primary local display (\c{:0}) if that fails.
2604 See \k{using-x-forwarding} for more information about X11
2607 \S{config-ssh-x11auth} Remote \i{X11 authentication}
2609 \cfg{winhelp-topic}{ssh.tunnels.x11auth}
2611 If you are using X11 forwarding, the virtual X server created on the
2612 SSH server machine will be protected by authorisation data. This
2613 data is invented, and checked, by PuTTY.
2615 The usual authorisation method used for this is called
2616 \i\cw{MIT-MAGIC-COOKIE-1}. This is a simple password-style protocol:
2617 the X client sends some cookie data to the server, and the server
2618 checks that it matches the real cookie. The cookie data is sent over
2619 an unencrypted X11 connection; so if you allow a client on a third
2620 machine to access the virtual X server, then the cookie will be sent
2623 PuTTY offers the alternative protocol \i\cw{XDM-AUTHORIZATION-1}. This
2624 is a cryptographically authenticated protocol: the data sent by the
2625 X client is different every time, and it depends on the IP address
2626 and port of the client's end of the connection and is also stamped
2627 with the current time. So an eavesdropper who captures an
2628 \cw{XDM-AUTHORIZATION-1} string cannot immediately re-use it for
2629 their own X connection.
2631 PuTTY's support for \cw{XDM-AUTHORIZATION-1} is a somewhat
2632 experimental feature, and may encounter several problems:
2634 \b Some X clients probably do not even support
2635 \cw{XDM-AUTHORIZATION-1}, so they will not know what to do with the
2636 data PuTTY has provided.
2638 \b This authentication mechanism will only work in SSH-2. In SSH-1,
2639 the SSH server does not tell the client the source address of
2640 a forwarded connection in a machine-readable format, so it's
2641 impossible to verify the \cw{XDM-AUTHORIZATION-1} data.
2643 \b You may find this feature causes problems with some SSH servers,
2644 which will not clean up \cw{XDM-AUTHORIZATION-1} data after a
2645 session, so that if you then connect to the same server using
2646 a client which only does \cw{MIT-MAGIC-COOKIE-1} and are allocated
2647 the same remote display number, you might find that out-of-date
2648 authentication data is still present on your server and your X
2651 PuTTY's default is \cw{MIT-MAGIC-COOKIE-1}. If you change it, you
2652 should be sure you know what you're doing.
2654 \H{config-ssh-portfwd} \I{port forwarding}The Tunnels panel
2656 \cfg{winhelp-topic}{ssh.tunnels.portfwd}
2658 The Tunnels panel allows you to configure tunnelling of arbitrary
2659 connection types through an SSH connection.
2661 Port forwarding allows you to tunnel other types of \i{network
2662 connection} down an SSH session. See \k{using-port-forwarding} for a
2663 general discussion of port forwarding and how it works.
2665 The port forwarding section in the Tunnels panel shows a list of all
2666 the port forwardings that PuTTY will try to set up when it connects
2667 to the server. By default no port forwardings are set up, so this
2670 To add a port forwarding:
2672 \b Set one of the \q{Local} or \q{Remote} radio buttons, depending
2673 on whether you want to \I{local port forwarding}forward a local port
2674 to a remote destination (\q{Local}) or \I{remote port forwarding}forward
2675 a remote port to a local destination (\q{Remote}). Alternatively,
2676 select \q{Dynamic} if you want PuTTY to \I{dynamic port forwarding}provide
2677 a local SOCKS 4/4A/5 proxy on a local port (note that this proxy only
2678 supports TCP connections; the SSH protocol does not support forwarding
2681 \b Enter a source \i{port number} into the \q{Source port} box. For
2682 local forwardings, PuTTY will listen on this port of your PC. For
2683 remote forwardings, your SSH server will listen on this port of the
2684 remote machine. Note that most servers will not allow you to listen
2685 on \I{privileged port}port numbers less than 1024.
2687 \b If you have selected \q{Local} or \q{Remote} (this step is not
2688 needed with \q{Dynamic}), enter a hostname and port number separated
2689 by a colon, in the \q{Destination} box. Connections received on the
2690 source port will be directed to this destination. For example, to
2691 connect to a POP-3 server, you might enter
2692 \c{popserver.example.com:110}.
2694 \b Click the \q{Add} button. Your forwarding details should appear
2697 To remove a port forwarding, simply select its details in the list
2698 box, and click the \q{Remove} button.
2700 In the \q{Source port} box, you can also optionally enter an \I{listen
2701 address}IP address to listen on, by specifying (for instance)
2703 See \k{using-port-forwarding} for more information on how this
2704 works and its restrictions.
2706 In place of port numbers, you can enter \i{service names}, if they are
2707 known to the local system. For instance, in the \q{Destination} box,
2708 you could enter \c{popserver.example.com:pop3}.
2710 You can \I{port forwarding, changing mid-session}modify the currently
2711 active set of port forwardings in mid-session using \q{Change
2712 Settings} (see \k{using-changesettings}). If you delete a local or
2713 dynamic port forwarding in mid-session, PuTTY will stop listening for
2714 connections on that port, so it can be re-used by another program. If
2715 you delete a remote port forwarding, note that:
2717 \b The SSH-1 protocol contains no mechanism for asking the server to
2718 stop listening on a remote port.
2720 \b The SSH-2 protocol does contain such a mechanism, but not all SSH
2721 servers support it. (In particular, \i{OpenSSH} does not support it in
2722 any version earlier than 3.9.)
2724 If you ask to delete a remote port forwarding and PuTTY cannot make
2725 the server actually stop listening on the port, it will instead just
2726 start refusing incoming connections on that port. Therefore,
2727 although the port cannot be reused by another program, you can at
2728 least be reasonably sure that server-side programs can no longer
2729 access the service at your end of the port forwarding.
2731 If you delete a forwarding, any existing connections established using
2732 that forwarding remain open. Similarly, changes to global settings
2733 such as \q{Local ports accept connections from other hosts} only take
2734 effect on new forwardings.
2736 \S{config-ssh-portfwd-localhost} Controlling the visibility of
2739 \cfg{winhelp-topic}{ssh.tunnels.portfwd.localhost}
2741 The source port for a forwarded connection usually does not accept
2742 connections from any machine except the \I{localhost}SSH client or
2743 server machine itself (for local and remote forwardings respectively).
2744 There are controls in the Tunnels panel to change this:
2746 \b The \q{Local ports accept connections from other hosts} option
2747 allows you to set up local-to-remote port forwardings in such a way
2748 that machines other than your client PC can connect to the forwarded
2749 port. (This also applies to dynamic SOCKS forwarding.)
2751 \b The \q{Remote ports do the same} option does the same thing for
2752 remote-to-local port forwardings (so that machines other than the
2753 SSH server machine can connect to the forwarded port.) Note that
2754 this feature is only available in the SSH-2 protocol, and not all
2755 SSH-2 servers support it (\i{OpenSSH} 3.0 does not, for example).
2757 \S{config-ssh-portfwd-address-family} Selecting \i{Internet protocol
2758 version} for forwarded ports
2760 \cfg{winhelp-topic}{ssh.tunnels.portfwd.ipversion}
2762 This switch allows you to select a specific Internet protocol (\i{IPv4}
2763 or \i{IPv6}) for the local end of a forwarded port. By default, it is
2764 set on \q{Auto}, which means that:
2766 \b for a local-to-remote port forwarding, PuTTY will listen for
2767 incoming connections in both IPv4 and (if available) IPv6
2769 \b for a remote-to-local port forwarding, PuTTY will choose a
2770 sensible protocol for the outgoing connection.
2772 Note that some operating systems may listen for incoming connections
2773 in IPv4 even if you specifically asked for IPv6, because their IPv4
2774 and IPv6 protocol stacks are linked together. Apparently \i{Linux} does
2775 this, and Windows does not. So if you're running PuTTY on Windows
2776 and you tick \q{IPv6} for a local or dynamic port forwarding, it
2777 will \e{only} be usable by connecting to it using IPv6; whereas if
2778 you do the same on Linux, you can also use it with IPv4. However,
2779 ticking \q{Auto} should always give you a port which you can connect
2780 to using either protocol.
2782 \H{config-ssh-bugs} \I{SSH server bugs}The Bugs panel
2784 Not all SSH servers work properly. Various existing servers have
2785 bugs in them, which can make it impossible for a client to talk to
2786 them unless it knows about the bug and works around it.
2788 Since most servers announce their software version number at the
2789 beginning of the SSH connection, PuTTY will attempt to detect which
2790 bugs it can expect to see in the server and automatically enable
2791 workarounds. However, sometimes it will make mistakes; if the server
2792 has been deliberately configured to conceal its version number, or
2793 if the server is a version which PuTTY's bug database does not know
2794 about, then PuTTY will not know what bugs to expect.
2796 The Bugs panel allows you to manually configure the bugs PuTTY
2797 expects to see in the server. Each bug can be configured in three
2800 \b \q{Off}: PuTTY will assume the server does not have the bug.
2802 \b \q{On}: PuTTY will assume the server \e{does} have the bug.
2804 \b \q{Auto}: PuTTY will use the server's version number announcement
2805 to try to guess whether or not the server has the bug.
2807 \S{config-ssh-bug-ignore1} \q{Chokes on SSH-1 \i{ignore message}s}
2809 \cfg{winhelp-topic}{ssh.bugs.ignore1}
2811 An ignore message (SSH_MSG_IGNORE) is a message in the SSH protocol
2812 which can be sent from the client to the server, or from the server
2813 to the client, at any time. Either side is required to ignore the
2814 message whenever it receives it. PuTTY uses ignore messages to
2815 \I{password camouflage}hide the password packet in SSH-1, so that
2816 a listener cannot tell the length of the user's password; it also
2817 uses ignore messages for connection \i{keepalives} (see
2818 \k{config-keepalive}).
2820 If this bug is detected, PuTTY will stop using ignore messages. This
2821 means that keepalives will stop working, and PuTTY will have to fall
2822 back to a secondary defence against SSH-1 password-length
2823 eavesdropping. See \k{config-ssh-bug-plainpw1}. If this bug is
2824 enabled when talking to a correct server, the session will succeed,
2825 but keepalives will not work and the session might be more
2826 vulnerable to eavesdroppers than it could be.
2828 This is an SSH-1-specific bug. No known SSH-2 server fails to deal
2829 with SSH-2 ignore messages.
2831 \S{config-ssh-bug-plainpw1} \q{Refuses all SSH-1 \i{password camouflage}}
2833 \cfg{winhelp-topic}{ssh.bugs.plainpw1}
2835 When talking to an SSH-1 server which cannot deal with ignore
2836 messages (see \k{config-ssh-bug-ignore1}), PuTTY will attempt to
2837 disguise the length of the user's password by sending additional
2838 padding \e{within} the password packet. This is technically a
2839 violation of the SSH-1 specification, and so PuTTY will only do it
2840 when it cannot use standards-compliant ignore messages as
2841 camouflage. In this sense, for a server to refuse to accept a padded
2842 password packet is not really a bug, but it does make life
2843 inconvenient if the server can also not handle ignore messages.
2845 If this \q{bug} is detected, PuTTY will assume that neither ignore
2846 messages nor padding are acceptable, and that it thus has no choice
2847 but to send the user's password with no form of camouflage, so that
2848 an eavesdropping user will be easily able to find out the exact length
2849 of the password. If this bug is enabled when talking to a correct
2850 server, the session will succeed, but will be more vulnerable to
2851 eavesdroppers than it could be.
2853 This is an SSH-1-specific bug. SSH-2 is secure against this type of
2856 \S{config-ssh-bug-rsa1} \q{Chokes on SSH-1 \i{RSA} authentication}
2858 \cfg{winhelp-topic}{ssh.bugs.rsa1}
2860 Some SSH-1 servers cannot deal with RSA authentication messages at
2861 all. If \i{Pageant} is running and contains any SSH-1 keys, PuTTY will
2862 normally automatically try RSA authentication before falling back to
2863 passwords, so these servers will crash when they see the RSA attempt.
2865 If this bug is detected, PuTTY will go straight to password
2866 authentication. If this bug is enabled when talking to a correct
2867 server, the session will succeed, but of course RSA authentication
2870 This is an SSH-1-specific bug.
2872 \S{config-ssh-bug-hmac2} \q{Miscomputes SSH-2 HMAC keys}
2874 \cfg{winhelp-topic}{ssh.bugs.hmac2}
2876 Versions 2.3.0 and below of the SSH server software from
2877 \cw{ssh.com} compute the keys for their \i{HMAC} \i{message authentication
2878 code}s incorrectly. A typical symptom of this problem is that PuTTY
2879 dies unexpectedly at the beginning of the session, saying
2880 \q{Incorrect MAC received on packet}.
2882 If this bug is detected, PuTTY will compute its HMAC keys in the
2883 same way as the buggy server, so that communication will still be
2884 possible. If this bug is enabled when talking to a correct server,
2885 communication will fail.
2887 This is an SSH-2-specific bug.
2889 \S{config-ssh-bug-derivekey2} \q{Miscomputes SSH-2 \i{encryption} keys}
2891 \cfg{winhelp-topic}{ssh.bugs.derivekey2}
2893 Versions below 2.0.11 of the SSH server software from \i\cw{ssh.com}
2894 compute the keys for the session encryption incorrectly. This
2895 problem can cause various error messages, such as \q{Incoming packet
2896 was garbled on decryption}, or possibly even \q{Out of memory}.
2898 If this bug is detected, PuTTY will compute its encryption keys in
2899 the same way as the buggy server, so that communication will still
2900 be possible. If this bug is enabled when talking to a correct
2901 server, communication will fail.
2903 This is an SSH-2-specific bug.
2905 \S{config-ssh-bug-sig} \q{Requires padding on SSH-2 \i{RSA} \i{signatures}}
2907 \cfg{winhelp-topic}{ssh.bugs.rsapad2}
2909 Versions below 3.3 of \i{OpenSSH} require SSH-2 RSA signatures to be
2910 padded with zero bytes to the same length as the RSA key modulus.
2911 The SSH-2 specification says that an unpadded signature MUST be
2912 accepted, so this is a bug. A typical symptom of this problem is
2913 that PuTTY mysteriously fails RSA authentication once in every few
2914 hundred attempts, and falls back to passwords.
2916 If this bug is detected, PuTTY will pad its signatures in the way
2917 OpenSSH expects. If this bug is enabled when talking to a correct
2918 server, it is likely that no damage will be done, since correct
2919 servers usually still accept padded signatures because they're used
2920 to talking to OpenSSH.
2922 This is an SSH-2-specific bug.
2924 \S{config-ssh-bug-pksessid2} \q{Misuses the \i{session ID} in SSH-2 PK auth}
2926 \cfg{winhelp-topic}{ssh.bugs.pksessid2}
2928 Versions below 2.3 of \i{OpenSSH} require SSH-2 \i{public-key authentication}
2929 to be done slightly differently: the data to be signed by the client
2930 contains the session ID formatted in a different way. If public-key
2931 authentication mysteriously does not work but the Event Log (see
2932 \k{using-eventlog}) thinks it has successfully sent a signature, it
2933 might be worth enabling the workaround for this bug to see if it
2936 If this bug is detected, PuTTY will sign data in the way OpenSSH
2937 expects. If this bug is enabled when talking to a correct server,
2938 SSH-2 public-key authentication will fail.
2940 This is an SSH-2-specific bug.
2942 \S{config-ssh-bug-rekey} \q{Handles SSH-2 key re-exchange badly}
2944 \cfg{winhelp-topic}{ssh.bugs.rekey2}
2946 Some SSH servers cannot cope with \i{repeat key exchange} at
2947 all, and will ignore attempts by the client to start one. Since
2948 PuTTY pauses the session while performing a repeat key exchange, the
2949 effect of this would be to cause the session to hang after an hour
2950 (unless you have your rekey timeout set differently; see
2951 \k{config-ssh-kex-rekey} for more about rekeys).
2952 Other, very old, SSH servers handle repeat key exchange even more
2953 badly, and disconnect upon receiving a repeat key exchange request.
2955 If this bug is detected, PuTTY will never initiate a repeat key
2956 exchange. If this bug is enabled when talking to a correct server,
2957 the session should still function, but may be less secure than you
2960 This is an SSH-2-specific bug.
2962 \H{config-serial} The Serial panel
2964 The \i{Serial} panel allows you to configure options that only apply
2965 when PuTTY is connecting to a local \I{serial port}\i{serial line}.
2967 \S{config-serial-line} Selecting a serial line to connect to
2969 \cfg{winhelp-topic}{serial.line}
2971 The \q{Serial line to connect to} box allows you to choose which
2972 serial line you want PuTTY to talk to, if your computer has more
2973 than one serial port.
2975 On Windows, the first serial line is called \i\cw{COM1}, and if there
2976 is a second it is called \cw{COM2}, and so on.
2978 This configuration setting is also visible on the Session panel,
2979 where it replaces the \q{Host Name} box (see \k{config-hostname}) if
2980 the connection type is set to \q{Serial}.
2982 \S{config-serial-speed} Selecting the speed of your serial line
2984 \cfg{winhelp-topic}{serial.speed}
2986 The \q{Speed} box allows you to choose the speed (or \q{baud rate})
2987 at which to talk to the serial line. Typical values might be 9600,
2988 19200, 38400 or 57600. Which one you need will depend on the device
2989 at the other end of the serial cable; consult the manual for that
2990 device if you are in doubt.
2992 This configuration setting is also visible on the Session panel,
2993 where it replaces the \q{Port} box (see \k{config-hostname}) if the
2994 connection type is set to \q{Serial}.
2996 \S{config-serial-databits} Selecting the number of data bits
2998 \cfg{winhelp-topic}{serial.databits}
3000 The \q{Data bits} box allows you to choose how many data bits are
3001 transmitted in each byte sent or received through the serial line.
3002 Typical values are 7 or 8.
3004 \S{config-serial-stopbits} Selecting the number of stop bits
3006 \cfg{winhelp-topic}{serial.stopbits}
3008 The \q{Stop bits} box allows you to choose how many stop bits are
3009 used in the serial line protocol. Typical values are 1, 1.5 or 2.
3011 \S{config-serial-parity} Selecting the serial parity checking scheme
3013 \cfg{winhelp-topic}{serial.parity}
3015 The \q{Parity} box allows you to choose what type of parity checking
3016 is used on the serial line. The settings are:
3018 \b \q{None}: no parity bit is sent at all.
3020 \b \q{Odd}: an extra parity bit is sent alongside each byte, and
3021 arranged so that the total number of 1 bits is odd.
3023 \b \q{Even}: an extra parity bit is sent alongside each byte, and
3024 arranged so that the total number of 1 bits is even.
3026 \b \q{Mark}: an extra parity bit is sent alongside each byte, and
3029 \b \q{Space}: an extra parity bit is sent alongside each byte, and
3032 \S{config-serial-flow} Selecting the serial flow control scheme
3034 \cfg{winhelp-topic}{serial.flow}
3036 The \q{Flow control} box allows you to choose what type of flow
3037 control checking is used on the serial line. The settings are:
3039 \b \q{None}: no flow control is done. Data may be lost if either
3040 side attempts to send faster than the serial line permits.
3042 \b \q{XON/XOFF}: flow control is done by sending XON and XOFF
3043 characters within the data stream.
3045 \b \q{RTS/CTS}: flow control is done using the RTS and CTS wires on
3048 \b \q{DSR/DTR}: flow control is done using the DSR and DTR wires on
3051 \H{config-file} \ii{Storing configuration in a file}
3053 PuTTY does not currently support storing its configuration in a file
3054 instead of the \i{Registry}. However, you can work around this with a
3055 couple of \i{batch file}s.
3057 You will need a file called (say) \c{PUTTY.BAT} which imports the
3058 contents of a file into the Registry, then runs PuTTY, exports the
3059 contents of the Registry back into the file, and deletes the
3060 Registry entries. This can all be done using the Regedit command
3061 line options, so it's all automatic. Here is what you need in
3065 \c regedit /s putty.reg
3066 \c regedit /s puttyrnd.reg
3067 \c start /w putty.exe
3068 \c regedit /ea new.reg HKEY_CURRENT_USER\Software\SimonTatham\PuTTY
3069 \c copy new.reg putty.reg
3071 \c regedit /s puttydel.reg
3073 This batch file needs two auxiliary files: \c{PUTTYRND.REG} which
3074 sets up an initial safe location for the \c{PUTTY.RND} random seed
3075 file, and \c{PUTTYDEL.REG} which destroys everything in the Registry
3076 once it's been successfully saved back to the file.
3078 Here is \c{PUTTYDEL.REG}:
3082 \c [-HKEY_CURRENT_USER\Software\SimonTatham\PuTTY]
3084 Here is an example \c{PUTTYRND.REG} file:
3088 \c [HKEY_CURRENT_USER\Software\SimonTatham\PuTTY]
3089 \c "RandSeedFile"="a:\\putty.rnd"
3091 You should replace \c{a:\\putty.rnd} with the location where you
3092 want to store your random number data. If the aim is to carry around
3093 PuTTY and its settings on one floppy, you probably want to store it