List open SSH tunnels

Solution 1:

if you only want to list tunnels created by ssh:

% sudo lsof -i -n | egrep '\<ssh\>'
ssh  19749  user  3u  IPv4 148088244   TCP x.x.x.x:39689->y.y.y.y:22 (ESTABLISHED)
ssh  19749  user  4u  IPv6 148088282   TCP [::1]:9090 (LISTEN)
ssh  19749  user  5u  IPv4 148088283   TCP 127.0.0.1:9090 (LISTEN)

(that would be a -L 9090:localhost:80 tunnel)

if you want to see the tunnels / connections made to a sshd:

 % sudo lsof -i -n | egrep '\<sshd\>'
sshd  15767  root  3u  IPv4 147401205   TCP x.x.x.x:22->y.y.y.y:27479 (ESTABLISHED)
sshd  15842  user  3u  IPv4 147401205   TCP x.x.x.x:22->y.y.y.y:27479 (ESTABLISHED)
sshd  15842  user  9u  IPv4 148002889   TCP 127.0.0.1:33999->127.0.0.1:www (ESTABLISHED)
sshd  1396   user  9u  IPv4 148056581   TCP 127.0.0.1:5000 (LISTEN)
sshd  25936  root  3u  IPv4 143971728   TCP *:22 (LISTEN)

the ssh-daemon listens on port 22 (last line), 2 subprocesses are spawned (first 2 lines, login of 'user'), a -R tunnel created on port 5000, and a -L tunnel which forwards a port from my (local) machine to localhost:80 (www).

Solution 2:

Try this command, it might be useful:

ps aux | grep ssh