SSH Tunnel Connection Failures

robert_at_sadev.co.za
Date: 01/24/05

  • Next message: Hrvoje Spoljar: "Re: Win32: Resuming secure uploads" 
    Date: 24 Jan 2005 05:51:19 -0800

    I'm setting up an SSH tunnel which initally works, but shortly (< 20s)
    after the connection is established I start getting error messages
    appearing and then the tunnel is no longer active.

    The setup is as follows:

    [ Machine A ] ----- [ SSH Server ] ----- [ Mail Server ]
    10.0.0.3 10.0.0.5 & 192.168.85.1
    192.168.85.12

    Tunnel is between Machine A and the SSH Server, for the purpose of SMTP
    traffic (TCP port 25) to the mail server.
    Machine A and the SSH Server can ping each other and the Mail Server
    and the SSH server can ping each other (obviously Machine A can't ping
    the Mail server because of the different network addresses).

    If I use this command on Machine A:
    # ssh -x -g -C -L 30001:192.168.85.1:25 10.0.0.5
    It gives this error message
    channel 2: open failed: connect failed: Connection refused

    If I use this command on Machine A:
    # ssh -x -g -C -N -T -L 30001:192.168.85.1:25 10.0.0.5
    It gives this error message
    channel 1: open failed: connect failed: Connection refused

    One further detail is that I am passing a lot of SMTP conenctions
    through the tunnel (> 3 connections per second).

    I'm thinking this is due to some limiting option in SSH, but I can not
    find anything.

    Any advice would be great :)

  • Next message: Hrvoje Spoljar: "Re: Win32: Resuming secure uploads"

    Relevant Pages

    • Re: What is The SSH?
      ... Building and Using SSH Tunnels ... What is an SSH tunnel? ... how to use it to make a connection to a server. ... You will need a working SSH client and server installation to build and test ...
      (microsoft.public.windows.server.networking)
    • SSH TCP forwarding: works with v1, not with v2 ssh
      ... that they're setting up the tunnels with no problem, ... I can get to the work ssh daemon: ... debug1: Connections to remote port 65002 forwarded to local address palimpsest:22 ... something answers (if I get "connection refused" there's no listener); ...
      (FreeBSD-Security)
    • Re: SSH TCP forwarding: works with v1, not with v2 ssh
      ... >that they're setting up the tunnels with no problem, ... >I can get to the work ssh daemon: ... > debug1: Entering interactive session. ... > Connection closed by foreign host. ...
      (FreeBSD-Security)
    • Re: sftp over two connections
      ... from there I log onto LIN and I can work on the console. ... > X tunneling works as well, and I tunnel additional ports to control ... > connection be tunneled through SSH so that I could mount LIN's ...
      (comp.security.ssh)
    • Re: PPP VPN solution over ssh tunnel?
      ... I run an ssh tunnel home from work all day long. ... I could run a traditional VPN connection ... but it worked for some things socks proxy did not. ...
      (comp.os.linux.networking)