Re: how to force an ssh client timeout

• Previous message: Alvin Oga: "Re: Locking down ssh config in large env"
• In reply to: k l: "Re: how to force an ssh client timeout"
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Date: Fri, 10 Sep 2004 16:49:57 -0700
To: k l <yoda_2732002@yahoo.com>

> I need to do this on the ssh client side e.g. if I
> can not log into a given machine in 10 seconds
> I want to terminate/close the connection and move
> on to the next machine. Please note that you may
> get/establish a TCP connection to the remote server but it
> may, for some reason, just stay/hang there and
> you may not be able to log in

Set up in your ssh connection a local port forward. Test
in 10 seconds if this forward is alive. If not, kill the connection.

Here's some perl-style pseudo code:

        sub sshto {
                $host=@_;

                if ( fork ) {
                        wait
                }
                $sshpid = fork();
                if ( $sshpid ) {
                        sleep 10;
                        use IO::Socket;
                        if ( IO::Socket::INET->new(
                               Proto => "tcp",
                               PeerAddr => "localhost",
                               PeerPort => $LOCALPORT
                         ) {
                                 exit;
                         } else {
                                 kill 9, $sshpid
                         }
                 } else {
                         exec "ssh -L $LOCALPORT:localhost:22 $SSH_ARGS $host"
                }
        }

Since the forward won't exist until ssh has logged in, you should
be able to catch if it's dead or not.

-- 
Brian Hatch                  "When I met him, he was
   Systems and                sullied and tainted.  But
   Security Engineer          now he has been purified
http://www.ifokr.org/bri/     in the fires of passion."
                              -- Bree
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• Previous message: Alvin Oga: "Re: Locking down ssh config in large env"
• In reply to: k l: "Re: how to force an ssh client timeout"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]