+\cfg{winhelp-topic}{ssh.command}
+
+In SSH, you don't have to run a general shell session on the server.
+Instead, you can choose to run a single specific command (such as a
+mail user agent, for example). If you want to do this, enter the
+command in the \q{Remote command} box.
+
+\S{config-ssh-pty} \q{Don't allocate a pseudo-terminal}
+
+\cfg{winhelp-topic}{ssh.nopty}
+
+When connecting to a Unix system, most 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-ssh-comp} \q{Enable compression}
+
+\cfg{winhelp-topic}{ssh.compress}
+
+This enables data compression in the SSH connection: data sent by
+the server is compressed before sending, and decompressed at the
+client end. Likewise, data sent by PuTTY to the server is compressed
+first and the server decompresses it at the other end. This can help
+make the most of a low-bandwidth connection.
+
+\S{config-ssh-prot} \q{Preferred SSH protocol version}
+
+\cfg{winhelp-topic}{ssh.protocol}
+
+This allows you to select whether you would like to use SSH protocol
+version 1 or version 2. \#{FIXME: say something about this elsewhere?}
+
+PuTTY will attempt to use protocol 1 if the server you connect to
+does not offer protocol 2, and vice versa.
+
+If you select \q{1 only} or \q{2 only} here, PuTTY will only connect
+if the server you connect to offers the SSH protocol version you
+have specified.
+
+\S{config-ssh-encryption} Encryption algorithm selection
+
+\cfg{winhelp-topic}{ssh.ciphers}
+
+PuTTY supports a variety of different encryption algorithms, and
+allows you to choose which one you prefer to use. You can do this by
+dragging the algorithms up and down in the list box (or moving them
+using the Up and Down buttons) to specify a preference order. When
+you make an SSH connection, PuTTY will search down the list from the
+top until it finds an algorithm supported by the server, and then
+use that.
+
+PuTTY currently supports the following algorithms:
+
+\b AES (Rijndael) - 256, 192, or 128-bit CBC (SSH-2 only)
+
+\b Blowfish - 128-bit CBC
+
+\b Triple-DES - 168-bit CBC
+
+\b Single-DES - 56-bit CBC (see below for SSH-2)
+
+If the algorithm PuTTY finds is below the \q{warn below here} line,
+you will see a warning box when you make the connection:
+
+\c The first cipher supported by the server
+\c is single-DES, which is below the configured
+\c warning threshold.
+\c Do you want to continue with this connection?
+
+This warns you that the first available encryption is not a very
+secure one. Typically you would put the \q{warn below here} line
+between the encryptions you consider secure and the ones you
+consider substandard. By default, PuTTY supplies a preference order
+intended to reflect a reasonable preference in terms of security and
+speed.
+
+In SSH-2, the encryption algorithm is negotiated independently for
+each direction of the connection, although PuTTY does not support
+separate configuration of the preference orders. As a result you may
+get two warnings similar to the one above, possibly with different
+encryptions.
+
+Single-DES is not supported natively in the SSH 2 draft protocol
+standards. One or two server implementations do support it, by a
+non-standard name. PuTTY can use single-DES to interoperate with
+these servers if you enable the \q{Enable non-standard single-DES in
+SSH 2} option; by default this is disabled and PuTTY will stick to
+the standard.
+
+\H{config-ssh-auth} The Auth panel
+
+The Auth panel allows you to configure authentication options for
+SSH sessions.
+
+\S{config-ssh-tis} \q{Attempt TIS or CryptoCard authentication}
+
+\cfg{winhelp-topic}{ssh.auth.tis}
+
+TIS and CryptoCard authentication are simple challenge/response
+forms of authentication available in SSH protocol version 1 only.
+You might use them if you were using S/Key one-time passwords, for
+example, or if you had a physical security token that generated
+responses to authentication challenges.
+
+With this switch enabled, PuTTY will attempt these forms of
+authentication if the server is willing to try them. You will be
+presented with a challenge string (which will be different every
+time) and must supply the correct response in order to log in. If
+your server supports this, you should talk to your system
+administrator about precisely what form these challenges and
+responses take.
+
+\S{config-ssh-ki} \q{Attempt keyboard-interactive authentication}
+
+\cfg{winhelp-topic}{ssh.auth.ki}
+
+The SSH 2 equivalent of TIS authentication is called
+\q{keyboard-interactive}. It is a flexible authentication method
+using an arbitrary sequence of requests and responses; so it is not
+only useful for challenge/response mechanisms such as S/Key, but it
+can also be used for (for example) asking the user for a new
+password when the old one has expired.
+
+PuTTY leaves this option enabled by default, but supplies a switch
+to turn it off in case you should have trouble with it.
+
+\S{config-ssh-agentfwd} \q{Allow agent forwarding}
+
+\cfg{winhelp-topic}{ssh.auth.agentfwd}
+
+This option allows the SSH server to open forwarded connections back
+to your local copy of Pageant. If you are not running Pageant, this
+option will do nothing.
+
+See \k{pageant} for general information on Pageant, and
+\k{pageant-forward} for information on agent forwarding. Note that
+there is a security risk involved with enabling this option; see
+\k{pageant-security} for details.
+
+\S{config-ssh-changeuser} \q{Allow attempted changes of username in SSH2}
+
+\cfg{winhelp-topic}{ssh.auth.changeuser}
+
+In the SSH 1 protocol, it is impossible to change username after
+failing to authenticate. So if you mis-type your username at the
+PuTTY \q{login as:} prompt, you will not be able to change it except
+by restarting PuTTY.
+
+The SSH 2 protocol \e{does} allow changes of username, in principle,
+but does not make it mandatory for SSH 2 servers to accept them. In
+particular, OpenSSH does not accept a change of username; once you
+have sent one username, it will reject attempts to try to
+authenticate as another user. (Depending on the version of OpenSSH,
+it may quietly return failure for all login attempts, or it may send
+an error message.)
+
+For this reason, PuTTY will by default not prompt you for your
+username more than once, in case the server complains. If you know
+your server can cope with it, you can enable the \q{Allow attempted
+changes of username} option to modify PuTTY's behaviour.
+
+\S{config-ssh-privkey} \q{Private key file for authentication}
+
+\cfg{winhelp-topic}{ssh.auth.privkey}
+
+This box is where you enter the name of your private key file if you
+are using public key authentication. See \k{pubkey} for information
+about public key authentication in SSH.
+
+This key must be in PuTTY's native format (\c{*.PPK}).
+
+\H{config-ssh-tunnels} The Tunnels panel
+
+The Tunnels panel allows you to configure tunnelling of other
+connection types through an SSH connection.
+
+\S{config-ssh-x11} X11 forwarding
+
+\cfg{winhelp-topic}{ssh.tunnels.x11}
+
+If your server lets you run X Window System applications, X11
+forwarding allows you to securely give those applications access to
+a local X display on your PC.
+
+To enable X11 forwarding, check the \q{Enable X11 forwarding} box.
+If your X display is not the primary display on your local machine
+(which it almost certainly will be unless you have deliberately
+arranged otherwise), you need to enter its location in the \q{X
+display location} box.
+
+See \k{using-x-forwarding} for more information about X11
+forwarding.
+
+\S2{config-ssh-x11auth} Remote X11 authentication
+
+\cfg{winhelp-topic}{ssh.tunnels.x11auth}
+
+If you are using X11 forwarding, the virtual X server created on the
+SSH server machine will be protected by authorisation data. This
+data is invented, and checked, by PuTTY.
+
+The usual authorisation method used for this is called
+\cw{MIT-MAGIC-COOKIE-1}. This is a simple password-style protocol:
+the X client sends some cookie data to the server, and the server
+checks that it matches the real cookie. The cookie data is sent over
+an unencrypted X11 connection; so if you allow a client on a third
+machine to access the virtual X server, then the cookie will be sent
+in the clear.
+
+PuTTY offers the alternative protocol \cw{XDM-AUTHORIZATION-1}. This
+is a cryptographically authenticated protocol: the data sent by the
+X client is different every time, and it depends on the IP address
+and port of the client's end of the connection and is also stamped
+with the current time. So an eavesdropper who captures an
+\cw{XDM-AUTHORIZATION-1} string cannot immediately re-use it for
+their own X connection.
+
+PuTTY's support for \cw{XDM-AUTHORIZATION-1} is a somewhat
+experimental feature, and may encounter several problems:
+
+\b Some X clients probably do not even support
+\cw{XDM-AUTHORIZATION-1}, so they will not know what to do with the
+data PuTTY has provided.
+
+\b This authentication mechanism will only work in SSH v2. In SSH
+v1, the SSH server does not tell the client the source address of
+a forwarded connection in a machine-readable format, so it's
+impossible to verify the \cw{XDM-AUTHORIZATION-1} data.
+
+\b You may find this feature causes problems with some SSH servers,
+which will not clean up \cw{XDM-AUTHORIZATION-1} data after a
+session, so that if you then connect to the same server using
+a client which only does \cw{MIT-MAGIC-COOKIE-1} and are allocated
+the same remote display number, you might find that out-of-date
+authentication data is still present on your server and your X
+connections fail.
+
+PuTTY's default is \cw{MIT-MAGIC-COOKIE-1}. If you change it, you
+should be sure you know what you're doing.
+
+\S{config-ssh-portfwd} Port forwarding
+
+\cfg{winhelp-topic}{ssh.tunnels.portfwd}
+
+Port forwarding allows you to tunnel other types of network
+connection down an SSH session. See \k{using-port-forwarding} for a
+general discussion of port forwarding and how it works.
+
+The port forwarding section in the Tunnels panel shows a list of all
+the port forwardings that PuTTY will try to set up when it connects
+to the server. By default no port forwardings are set up, so this
+list is empty.
+
+To add a port forwarding:
+
+\b Set one of the \q{Local} or \q{Remote} radio buttons, depending
+on whether you want to forward a local port to a remote destination
+(\q{Local}) or forward a remote port to a local destination
+(\q{Remote}). Alternatively, select \q{Dynamic} if you want PuTTY to
+provide a local SOCKS proxy on a local port.
+
+\b Enter a source port number into the \q{Source port} box. For
+local forwardings, PuTTY will listen on this port of your PC. For
+remote forwardings, your SSH server will listen on this port of the
+remote machine. Note that most servers will not allow you to listen
+on port numbers less than 1024.
+
+\b If you have selected \q{Local} or \q{Remote} (this step is not
+needed with \q{Dynamic}), enter a hostname and port number separated
+by a colon, in the \q{Destination} box. Connections received on the
+source port will be directed to this destination. For example, to
+connect to a POP-3 server, you might enter
+\c{popserver.example.com:110}.
+
+\b Click the \q{Add} button. Your forwarding details should appear
+in the list box.
+
+To remove a port forwarding, simply select its details in the list
+box, and click the \q{Remove} button.
+
+In the \q{Source port} box, you can also optionally enter an IP
+address to listen on. Typically a Windows machine can be asked to
+listen on any single IP address in the \cw{127.*.*.*} range, and all
+of these are loopback addresses available only to the local machine.
+So if you forward (for example) \c{127.0.0.5:79} to a remote
+machine's \cw{finger} port, then you should be able to run commands
+such as \c{finger fred@127.0.0.5}. This can be useful if the program
+connecting to the forwarded port doesn't allow you to change the
+port number it uses. This feature is available for local-to-remote
+forwarded ports; SSH1 is unable to support it for remote-to-local
+ports, while SSH2 can support it in theory but servers will not
+necessarily cooperate.
+
+\S{config-ssh-portfwd-localhost} Controlling the visibility of
+forwarded ports
+
+\cfg{winhelp-topic}{ssh.tunnels.portfwd.localhost}
+
+The source port for a forwarded connection usually does not accept
+connections from any machine except the SSH client or server machine
+itself (for local and remote forwardings respectively). There are
+controls in the Tunnels panel to change this:
+
+\b The \q{Local ports accept connections from other hosts} option
+allows you to set up local-to-remote port forwardings in such a way
+that machines other than your client PC can connect to the forwarded
+port. (This also applies to dynamic SOCKS forwarding.)
+
+\b The \q{Remote ports do the same} option does the same thing for
+remote-to-local port forwardings (so that machines other than the
+SSH server machine can connect to the forwarded port.) Note that
+this feature is only available in the SSH 2 protocol, and not all
+SSH 2 servers support it (OpenSSH 3.0 does not, for example).
+
+\H{config-ssh-bugs} The Bugs panel
+
+Not all SSH servers work properly. Various existing servers have
+bugs in them, which can make it impossible for a client to talk to
+them unless it knows about the bug and works around it.
+
+Since most servers announce their software version number at the
+beginning of the SSH connection, PuTTY will attempt to detect which
+bugs it can expect to see in the server and automatically enable
+workarounds. However, sometimes it will make mistakes; if the server
+has been deliberately configured to conceal its version number, or
+if the server is a version which PuTTY's bug database does not know
+about, then PuTTY will not know what bugs to expect.
+
+The Bugs panel allows you to manually configure the bugs PuTTY
+expects to see in the server. Each bug can be configured in three
+states:
+
+\b \q{Off}: PuTTY will assume the server does not have the bug.
+
+\b \q{On}: PuTTY will assume the server \e{does} have the bug.
+
+\b \q{Auto}: PuTTY will use the server's version number announcement
+to try to guess whether or not the server has the bug.
+
+\S{config-ssh-bug-ignore1} \q{Chokes on SSH1 ignore messages}
+
+\cfg{winhelp-topic}{ssh.bugs.ignore1}
+
+An ignore message (SSH_MSG_IGNORE) is a message in the SSH protocol
+which can be sent from the client to the server, or from the server
+to the client, at any time. Either side is required to ignore the
+message whenever it receives it. PuTTY uses ignore messages to hide
+the password packet in SSH1, so that a listener cannot tell the
+length of the user's password; it also uses ignore messages for
+connection keepalives (see \k{config-keepalive}).
+
+If this bug is detected, PuTTY will stop using ignore messages. This
+means that keepalives will stop working, and PuTTY will have to fall
+back to a secondary defence against SSH1 password-length
+eavesdropping. See \k{config-ssh-bug-plainpw1}. If this bug is
+enabled when talking to a correct server, the session will succeed,
+but keepalives will not work and the session might be more
+vulnerable to eavesdroppers than it could be.
+
+This is an SSH1-specific bug. No known SSH2 server fails to deal
+with SSH2 ignore messages.
+
+\S{config-ssh-bug-plainpw1} \q{Refuses all SSH1 password camouflage}
+
+\cfg{winhelp-topic}{ssh.bugs.plainpw1}
+
+When talking to an SSH1 server which cannot deal with ignore
+messages (see \k{config-ssh-bug-ignore1}), PuTTY will attempt to
+disguise the length of the user's password by sending additional
+padding \e{within} the password packet. This is technically a
+violation of the SSH1 specification, and so PuTTY will only do it
+when it cannot use standards-compliant ignore messages as
+camouflage. In this sense, for a server to refuse to accept a padded
+password packet is not really a bug, but it does make life
+inconvenient if the server can also not handle ignore messages.
+
+If this \q{bug} is detected, PuTTY will have no choice but to send
+the user's password with no form of camouflage, so that an
+eavesdropping user will be easily able to find out the exact length
+of the password. If this bug is enabled when talking to a correct
+server, the session will succeed, but will be more vulnerable to
+eavesdroppers than it could be.
+
+This is an SSH1-specific bug. SSH2 is secure against this type of
+attack.
+
+\S{config-ssh-bug-rsa1} \q{Chokes on SSH1 RSA authentication}
+
+\cfg{winhelp-topic}{ssh.bugs.rsa1}
+
+Some SSH1 servers cannot deal with RSA authentication messages at
+all. If Pageant is running and contains any SSH1 keys, PuTTY will
+normally automatically try RSA authentication before falling back to
+passwords, so these servers will crash when they see the RSA attempt.
+
+If this bug is detected, PuTTY will go straight to password
+authentication. If this bug is enabled when talking to a correct
+server, the session will succeed, but of course RSA authentication
+will be impossible.
+
+This is an SSH1-specific bug.
+
+\S{config-ssh-bug-hmac2} \q{Miscomputes SSH2 HMAC keys}
+
+\cfg{winhelp-topic}{ssh.bugs.hmac2}
+
+Versions 2.3.0 and below of the SSH server software from
+\cw{ssh.com} compute the keys for their HMAC message authentication
+codes incorrectly. A typical symptom of this problem is that PuTTY
+dies unexpectedly at the beginning of the session, saying
+\q{Incorrect MAC received on packet}.
+
+If this bug is detected, PuTTY will compute its HMAC keys in the
+same way as the buggy server, so that communication will still be
+possible. If this bug is enabled when talking to a correct server,
+communication will fail.
+
+This is an SSH2-specific bug.
+
+\S{config-ssh-bug-derivekey2} \q{Miscomputes SSH2 encryption keys}
+
+\cfg{winhelp-topic}{ssh.bugs.derivekey2}
+
+Versions below 2.0.11 of the SSH server software from \cw{ssh.com}
+compute the keys for the session encryption incorrectly. This
+problem can cause various error messages, such as \q{Incoming packet
+was garbled on decryption}, or possibly even \q{Out of memory}.
+
+If this bug is detected, PuTTY will compute its encryption keys in
+the same way as the buggy server, so that communication will still
+be possible. If this bug is enabled when talking to a correct
+server, communication will fail.
+
+This is an SSH2-specific bug.
+
+\S{config-ssh-bug-sig} \q{Requires padding on SSH2 RSA signatures}
+
+\cfg{winhelp-topic}{ssh.bugs.rsapad2}
+
+Versions below 3.3 of OpenSSH require SSH2 RSA signatures to be
+padded with zero bytes to the same length as the RSA key modulus.
+The SSH2 draft specification says that an unpadded signature MUST be
+accepted, so this is a bug. A typical symptom of this problem is
+that PuTTY mysteriously fails RSA authentication once in every few
+hundred attempts, and falls back to passwords.
+
+If this bug is detected, PuTTY will pad its signatures in the way
+OpenSSH expects. If this bug is enabled when talking to a correct
+server, it is likely that no damage will be done, since correct
+servers usually still accept padded signatures because they're used
+to talking to OpenSSH.
+
+This is an SSH2-specific bug.
+
+\S{config-ssh-bug-dhgex} \q{Chokes on Diffie-Hellman group exchange}
+
+\cfg{winhelp-topic}{ssh.bugs.dhgex2}
+
+We have anecdotal evidence that some SSH servers claim to be able to
+perform Diffie-Hellman group exchange, but fail to actually do so
+when PuTTY tries to. If your SSH2 sessions spontaneously close
+immediately after opening the PuTTY window, it might be worth
+enabling the workaround for this bug to see if it helps.
+
+We have no hard evidence that any specific version of specific
+server software reliably demonstrates this bug. Therefore, PuTTY
+will never \e{assume} a server has this bug; if you want the
+workaround, you need to enable it manually.
+
+This is an SSH2-specific bug.
+
+\S{config-ssh-bug-pksessid2} \q{Misuses the session ID in PK auth}
+
+\cfg{winhelp-topic}{ssh.bugs.pksessid2}
+
+Versions below 2.3 of OpenSSH require SSH2 public-key authentication
+to be done slightly differently: the data to be signed by the client
+contains the session ID formatted in a different way. If public-key
+authentication mysteriously does not work but the Event Log (see
+\k{using-eventlog}) thinks it has successfully sent a signature, it
+might be worth enabling the workaround for this bug to see if it
+helps.
+
+If this bug is detected, PuTTY will sign data in the way OpenSSH
+expects. If this bug is enabled when talking to a correct server,
+SSH2 public-key authentication will fail.