Ssh – How to get list of open SSH tunnels

sshssh-tunnel

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.

Best Answer

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).

Related Solutions

Ssh – Why are the reverse SSH tunnels suddenly dying

Has there been any change in the network setup around your server? I've seen this happen when a router or firewall which the traffic goes through does not keep the state of a TCP connection when there's no traffic.

Try adding this to the ssh_config on your server:

ServerAliveInterval 60

This will send some data through the ssh connection (It won't interfere with your tunnels) every minute so that whatever might be timing out your connection will not forget about it. It has the added bonus of killing your ssh tunnels automatically if it's not responsive anymore, which would allow your existing script to reconnect.

SSH Authentication – Use Only Password and Ignore SSH Key

Try ssh -o PasswordAuthentication=yes -o PreferredAuthentications=keyboard-interactive,password -o PubkeyAuthentication=no host.example.org

In ssh v2, keyboard-interactive is another way to say "password". The -o PubkeyAuthentication=no option instructs the client not to attempt key pair authentication.

In addition, the PasswordAuthentication=yes option is to override any previously configured ssh options that may have disabled it.

Best Answer

Related Solutions

Ssh – Why are the reverse SSH tunnels suddenly dying

SSH Authentication – Use Only Password and Ignore SSH Key

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