martin@martin:~$ ssh -R 0.0.0.0:2233:127.0.0.1:22 [email protected]

[email protected]:~$ sudo -s

[email protected]:/home/martin# lsof -i:2233
COMMAND   PID   USER   FD   TYPE  DEVICE SIZE/OFF NODE NAME
sshd    25939 martin    8u  IPv6 5429774      0t0  TCP localhost:2233 (LISTEN)
sshd    25939 martin    9u  IPv4 5429775      0t0  TCP localhost:2233 (LISTEN)
[email protected]:/home/martin#