Cross-reference all the host key docs.

[PuTTY.git] / doc / using.but

diff --git a/doc/using.but b/doc/using.but
index 0a05c2e27d35bbcaa4fe371fbe1f15b44ba89b59..dc0d6b9b4a691194347eb2e0463d5418047c28e1 100644 (file)
--- a/doc/using.but
+++ b/doc/using.but
@@ -201,6 +201,28 @@ resets associated timers and counters). For more information about
 repeat key exchanges, see \k{config-ssh-kex-rekey}.
 }
 
 repeat key exchanges, see \k{config-ssh-kex-rekey}.
 }
 

+\b \I{host key cache}Cache new host key type
+
+\lcont{
+Only available in SSH-2. This submenu appears only if the server has
+host keys of a type that PuTTY doesn't already have cached, and so
+won't use. Selecting a key here will allow PuTTY to use that key now
+and in future: PuTTY will do key here will cause a fresh key-exchange
+with the selected key, and immediately add that key to PuTTY's
+permanent cache (relying on the host key used at the start of the
+connection to cross-certify the new key). That key will be used for
+the rest of the current session; it may not actually be used for
+future sessions.
+
+Normally, PuTTY will carry on using a host key it already knows, even
+if the server offers key formats that PuTTY would otherwise prefer,
+to avoid host key prompts. As a result, if you've been using a server
+for some years, you may still be using an older key than a new user
+would use, due to server upgrades in the meantime. The SSH protocol
+unfortunately does not have organised facilities for host key migration
+and rollover, but this allows you to manually upgrade.
+}
+

 \b \I{Break, SSH special command}Break
 
 \lcont{
 \b \I{Break, SSH special command}Break
 
 \lcont{


@@ -912,22 +934,22 @@ authentication} box in the Auth panel of the PuTTY configuration box
 \S2{using-cmdline-loghost} \i\c{-loghost}: specify a \i{logical host
 name}
 
 \S2{using-cmdline-loghost} \i\c{-loghost}: specify a \i{logical host
 name}
 

-This option overrides PuTTY's normal SSH host key caching policy by
-telling it the name of the host you expect your connection to end up
-at (in cases where this differs from the location PuTTY thinks it's
-connecting to). It can be a plain host name, or a host name followed
-by a colon and a port number. See \k{config-loghost} for more detail
-on this.
+This option overrides PuTTY's normal SSH \I{host key cache}host key
+caching policy by telling it the name of the host you expect your
+connection to end up at (in cases where this differs from the location
+PuTTY thinks it's connecting to). It can be a plain host name, or a
+host name followed by a colon and a port number. See
+\k{config-loghost} for more detail on this.

 
 \S2{using-cmdline-hostkey} \i\c{-hostkey}: \I{manually configuring
 host keys}manually specify an expected host key
 
 
 \S2{using-cmdline-hostkey} \i\c{-hostkey}: \I{manually configuring
 host keys}manually specify an expected host key
 

-This option overrides PuTTY's normal SSH host key caching policy by
-telling it exactly what host key to expect, which can be useful if the
-normal automatic host key store in the Registry is unavailable. The
-argument to this option should be either a host key fingerprint, or an
-SSH-2 public key blob. See \k{config-ssh-kex-manual-hostkeys} for more
-information.
+This option overrides PuTTY's normal SSH \I{host key cache}host key
+caching policy by telling it exactly what host key to expect, which
+can be useful if the normal automatic host key store in the Registry
+is unavailable. The argument to this option should be either a host key
+fingerprint, or an SSH-2 public key blob. See
+\k{config-ssh-kex-manual-hostkeys} for more information.

 
 You can specify this option more than once if you want to configure
 more than one key to be accepted.
 
 You can specify this option more than once if you want to configure
 more than one key to be accepted.