OpenSSH

SSH Tunneling

ssh -2 -N -f -L 6669:irc.linpro.no:6667 user@pichove.org

... will create a tunnel from localhost:6669 to irc.linpro.no:6667 through pichove.org

ssh -2 -N -R 6669:irc.linpro.no:6667 user@pichove.org

... will create a tunnel from localhost:6669 on pichove.org to irc.linpro.no:6667 through the machine currently running the process

ssh -2 -N -n -T -D 9999 user@pichove.org

... will create a tunnel from localhost:9999 to pichove.org (SOCKS)

Argument description

• -2 Forces ssh to use version 2 of the protocol
• -D Specifies a local “dynamic” application-level port forwarding. ssh will act as a SOCKS server.
• -f Forces ssh to run in the background
• -L Indicates a local tunnel in localport:remotehost:remoteport fashion
• -N Indicates no command, or tunnel only. If omitted, ssh would initiate a normal session
• -n Redirects stdin from /dev/null
• -R Indicates a remote tunnel in localport:remotehost:remoteport fashion
• -T Disables pseudo-tty allocation

Key manipulation

ssh-keygen -f <priv-key-file> -p

... changes the private key password

ssh-keygen -l -E md5 -f <pub-key-file>

... displays MD5 fingerprint of the public key