http://blog.koehntopp.de/archives/2703-ssh-durch-den-Gateway-Host.html
config
ServerAliveInterval 10 ServerAliveCountMax 3 Compression yes HashKnownHosts no TCPKeepAlive yes ControlMaster auto ControlPath ~/.ssh/ssh_control_%h_%p_%r Host router Hostname name.homeunix.org User name Port 4444 Host desktop Hostname 192.168.1.2 User name Port 22 ProxyCommand ssh router nc -w30 %h %p LocalForward 6667 127.0.0.1:6667 LocalForward 1993 127.0.0.1:993 LocalForward 1587 127.0.0.1:587 LocalForward 1999 news.mein-freund.de:119 DynamicForward 1080 Host * ForwardAgent yes