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Eonil
Asked: 2011-03-11 18:48:27 +0800 CST

How can I get list of open SSH tunnels?

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How can I get list of open SSH tunnels?

I'm using Mac OS X client connected to FreeBSD server. I'm trying to query open tunnels on the client.

ssh ssh-tunnel

5 Answers

  1. You can use lsof:

    $ lsof -i tcp | grep ^ssh
ssh       2211 lcipriani    3r  IPv4  20825      0t0  TCP lcipriani-laptop.local:49164->docsuite.cefla.com:22 (ESTABLISHED)
ssh       2223 lcipriani    3r  IPv4  21945      0t0  TCP lcipriani-laptop.local:34471->gd-b-21.vps.redomino.com:22 (ESTABLISHED)
ssh       2640 lcipriani    3r  IPv4  37488      0t0  TCP lcipriani-laptop.local:45693->makeda-xen1.redomino.com:22 (ESTABLISHED)
ssh       5279 lcipriani    3r  IPv4 212324      0t0  TCP lcipriani-laptop.local:56491->67.227.82.162:22 (ESTABLISHED)
ssh       5279 lcipriani    4u  IPv6 210281      0t0  TCP lcipriani-laptop:10000 (LISTEN)
ssh       5279 lcipriani    5u  IPv4 210282      0t0  TCP localhost.localdomain:10000 (LISTEN)

    The last line represent a tunnel (look at the state LISTEN).

    • 12

  2. In Ubuntu, with iptables and iptstate installed and standard ssh port:

    iptstate -D 22

    each line will represent open tunnel.

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  3. If you're trying to find out what's using the tunnel(s) in a single ssh session, type ~# at the beginning of a line.

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  4. /sbin/ip tunnel list # replacement for the deprecated iptunnel command
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  5. Using lcipriani's answer in a script:

    sessions=$(lsof -i tcp | grep "^ssh" | grep ESTABLISHED)
if [ -z "sessions" ]; then
    echo "no open ssh sessions"
else
    echo "ssh sessions are open"
fi
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