X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/7374c7790ee32f36855e4257eb15d2fe43e277ea..bb7328d0c61c6e779a6cf33b48c04511334fef9c:/doc/using.but

diff --git a/doc/using.but b/doc/using.but
index 0fb7127b..17fdce5f 100644
--- a/doc/using.but
+++ b/doc/using.but
@@ -123,9 +123,10 @@ Event Log into your bug report.
 
 Depending on the protocol used for the current session, there may be
 a submenu of \q{special commands}. These are protocol-specific
-tokens, such as a \i{\q{break} signal}, that can be sent down a
+tokens, such as a \q{break} signal, that can be sent down a
 connection in addition to normal data. Their precise effect is usually
-up to the server. Currently only Telnet and SSH have special commands.
+up to the server. Currently only Telnet, SSH, and serial connections
+have special commands.
 
 The following \I{Telnet special commands}special commands are
 available in Telnet:
@@ -207,6 +208,9 @@ Only available in SSH-2, and only during a session. Sends various
 POSIX signals. Not honoured by all servers.
 }
 
+With a serial connection, the only available special command is
+\I{Break, serial special command}\q{Break}.
+
 \S2{using-newsession} Starting new sessions
 
 PuTTY's system menu provides some shortcut ways to start new
@@ -796,6 +800,47 @@ at all} checkbox in the SSH panel of the PuTTY configuration box
 This option is not available in the file transfer tools PSCP and
 PSFTP.
 
+\S2{using-cmdline-ncmode} \I{-nc}\c{-nc}: make a \i{remote network
+connection} in place of a remote shell or command
+
+The \c{-nc} option prevents Plink (or PuTTY) from attempting to
+start a shell or command on the remote server. Instead, it will
+instruct the remote server to open a network connection to a host
+name and port number specified by you, and treat that network
+connection as if it were the main session.
+
+You specify a host and port as an argument to the \c{-nc} option,
+with a colon separating the host name from the port number, like
+this:
+
+\c plink host1.example.com -nc host2.example.com:1234
+
+You might want to use this feature if you needed to make an SSH
+connection to a target host which you can only reach by going
+through a proxy host, and rather than using port forwarding you
+prefer to use the local proxy feature (see \k{config-proxy-type} for
+more about local proxies). In this situation you might select
+\q{Local} proxy type, set your local proxy command to be \cq{plink
+%proxyhost -nc %host:%port}, enter the target host name on the
+Session panel, and enter the directly reachable proxy host name on
+the Proxy panel.
+
+This feature is only available in SSH protocol version 2 (since the
+version 1 protocol assumes you will always want to run a shell). It
+is not available in the file transfer tools PSCP and PSFTP. It is
+available in PuTTY itself, although it is unlikely to be very useful
+in any tool other than Plink. Also, \c{-nc} uses the same server
+functionality as port forwarding, so it will not work if your server
+administrator has disabled port forwarding.
+
+(The option is named \c{-nc} after the Unix program
+\W{http://www.vulnwatch.org/netcat/}\c{nc}, short for \q{netcat}.
+The command \cq{plink host1 -nc host2:port} is very similar in
+functionality to \cq{plink host1 nc host2 port}, which invokes
+\c{nc} on the server and tells it to connect to the specified
+destination. However, Plink's built-in \c{-nc} option does not
+depend on the \c{nc} program being installed on the server.)
+
 \S2{using-cmdline-compress} \I{-C-upper}\c{-C}: enable \i{compression}
 
 The \c{-C} option enables compression of the data sent across the