+This key must be in PuTTY's native format (\c{*.\i{PPK}}). If you have a
+private key in another format that you want to use with PuTTY, see
+\k{puttygen-conversions}.
+
+You can use the authentication agent \i{Pageant} so that you do not
+need to explicitly configure a key here; see \k{pageant}.
+
+If a private key file is specified here with Pageant running, PuTTY
+will first try asking Pageant to authenticate with that key, and
+ignore any other keys Pageant may have. If that fails, PuTTY will ask
+for a passphrase as normal. You can also specify a \e{public} key file
+in this case (in RFC 4716 or OpenSSH format), as that's sufficient to
+identify the key to Pageant, but of course if Pageant isn't present
+PuTTY can't fall back to using this file itself.
+
+\H{config-ssh-auth-gssapi} The \i{GSSAPI} panel
+
+\cfg{winhelp-topic}{ssh.auth.gssapi}
+
+The \q{GSSAPI} subpanel of the \q{Auth} panel controls the use of
+GSSAPI authentication. This is a mechanism which delegates the
+authentication exchange to a library elsewhere on the client
+machine, which in principle can authenticate in many different ways
+but in practice is usually used with the \i{Kerberos} \i{single sign-on}
+protocol to implement \i{passwordless login}.
+
+GSSAPI is only available in the SSH-2 protocol.
+
+The topmost control on the GSSAPI subpanel is the checkbox labelled
+\q{Attempt GSSAPI authentication}. If this is disabled, GSSAPI will
+not be attempted at all and the rest of this panel is unused. If it
+is enabled, GSSAPI authentication will be attempted, and (typically)
+if your client machine has valid Kerberos credentials loaded, then
+PuTTY should be able to authenticate automatically to servers that
+support Kerberos logins.
+
+\S{config-ssh-auth-gssapi-delegation} \q{Allow GSSAPI credential
+delegation}
+
+\cfg{winhelp-topic}{ssh.auth.gssapi.delegation}
+
+\i{GSSAPI credential delegation} is a mechanism for passing on your
+Kerberos (or other) identity to the session on the SSH server. If
+you enable this option, then not only will PuTTY be able to log in
+automatically to a server that accepts your Kerberos credentials,
+but also you will be able to connect out from that server to other
+Kerberos-supporting services and use the same credentials just as
+automatically.
+
+(This option is the Kerberos analogue of SSH agent forwarding; see
+\k{pageant-forward} for some information on that.)
+
+Note that, like SSH agent forwarding, there is a security
+implication in the use of this option: the administrator of the
+server you connect to, or anyone else who has cracked the
+administrator account on that server, could fake your identity when
+connecting to further Kerberos-supporting services. However,
+Kerberos sites are typically run by a central authority, so the
+administrator of one server is likely to already have access to the
+other services too; so this would typically be less of a risk than
+SSH agent forwarding.
+
+\S{config-ssh-auth-gssapi-libraries} Preference order for GSSAPI
+libraries
+
+\cfg{winhelp-topic}{ssh.auth.gssapi.libraries}
+
+GSSAPI is a mechanism which allows more than one authentication
+method to be accessed through the same interface. Therefore, more
+than one authentication library may exist on your system which can
+be accessed using GSSAPI.
+
+PuTTY contains native support for a few well-known such libraries,
+and will look for all of them on your system and use whichever it
+finds. If more than one exists on your system and you need to use a
+specific one, you can adjust the order in which it will search using
+this preference list control.
+
+One of the options in the preference list is to use a user-specified
+GSSAPI library. If the library you want to use is not mentioned by
+name in PuTTY's list of options, you can enter its full pathname in
+the \q{User-supplied GSSAPI library path} field, and move the
+\q{User-supplied GSSAPI library} option in the preference list to
+make sure it is selected before anything else.
+
+\H{config-ssh-tty} The TTY panel
+
+The TTY panel lets you configure the remote pseudo-terminal.
+
+\S{config-ssh-pty} \I{pseudo-terminal allocation}\q{Don't allocate
+a pseudo-terminal}
+
+\cfg{winhelp-topic}{ssh.nopty}
+
+When connecting to a \i{Unix} system, most \I{interactive
+connections}interactive shell sessions are run in a \e{pseudo-terminal},
+which allows the Unix system to pretend it's talking to a real physical
+terminal device but allows the SSH server to catch all the data coming
+from that fake device and send it back to the client.
+
+Occasionally you might find you have a need to run a session \e{not}
+in a pseudo-terminal. In PuTTY, this is generally only useful for
+very specialist purposes; although in Plink (see \k{plink}) it is
+the usual way of working.
+
+\S{config-ttymodes} Sending \i{terminal modes}
+
+\cfg{winhelp-topic}{ssh.ttymodes}
+
+The SSH protocol allows the client to send \q{terminal modes} for
+the remote pseudo-terminal. These usually control the server's
+expectation of the local terminal's behaviour.
+
+If your server does not have sensible defaults for these modes, you
+may find that changing them here helps. If you don't understand any of
+this, it's safe to leave these settings alone.
+
+(None of these settings will have any effect if no pseudo-terminal
+is requested or allocated.)
+
+You can add or modify a mode by selecting it from the drop-down list,
+choosing whether it's set automatically or to a specific value with
+the radio buttons and edit box, and hitting \q{Add}. A mode (or
+several) can be removed from the list by selecting them and hitting
+\q{Remove}. The effect of the mode list is as follows:
+
+\b If a mode is not on the list, it will not be specified to the
+server under any circumstances.
+
+\b If a mode is on the list:
+
+\lcont{
+
+\b If the \q{Auto} option is selected, the PuTTY tools will decide
+whether to specify that mode to the server, and if so, will send
+a sensible value.
+
+\lcont{
+
+PuTTY proper will send modes that it has an opinion on (currently only
+the code for the Backspace key, \cw{ERASE}). Plink on Unix
+will propagate appropriate modes from the local terminal, if any.
+
+}
+
+\b If a value is specified, it will be sent to the server under all
+circumstances. The precise syntax of the value box depends on the
+mode.
+
+}
+
+By default, all of the available modes are listed as \q{Auto},
+which should do the right thing in most circumstances.
+
+The precise effect of each setting, if any, is up to the server. Their
+names come from \i{POSIX} and other Unix systems, and they are most
+likely to have a useful effect on such systems. (These are the same
+settings that can usually be changed using the \i\c{stty} command once
+logged in to such servers.)
+
+Some notable modes are described below; for fuller explanations, see
+your server documentation.
+
+\b \I{ERASE special character}\cw{ERASE} is the character that when typed
+by the user will delete one space to the left. When set to \q{Auto}
+(the default setting), this follows the setting of the local Backspace
+key in PuTTY (see \k{config-backspace}).
+
+\lcont{
+This and other \i{special character}s are specified using \c{^C} notation
+for Ctrl-C, and so on. Use \c{^<27>} or \c{^<0x1B>} to specify a
+character numerically, and \c{^~} to get a literal \c{^}. Other
+non-control characters are denoted by themselves. Leaving the box
+entirely blank indicates that \e{no} character should be assigned to
+the specified function, although this may not be supported by all
+servers.
+}
+
+\b \I{QUIT special character}\cw{QUIT} is a special character that
+usually forcefully ends the current process on the server
+(\cw{SIGQUIT}). On many servers its default setting is Ctrl-backslash
+(\c{^\\}), which is easy to accidentally invoke on many keyboards. If
+this is getting in your way, you may want to change it to another
+character or turn it off entirely.
+
+\b Boolean modes such as \cw{ECHO} and \cw{ICANON} can be specified in
+PuTTY in a variety of ways, such as \cw{true}/\cw{false},
+\cw{yes}/\cw{no}, and \cw{0}/\cw{1}.
+
+\b Terminal speeds are configured elsewhere; see \k{config-termspeed}.