SSH tunneling

Sooner or later you need a tunnel to your home, work or server, and the easiest way to build one is SSH. There are plenty of manuals online; here I keep my own examples with descriptions.

• Local port forwarding: ssh -2 -f -N -L local_port:127.0.0.1:remote_port user@host
  • -2 – force SSH protocol version 2 only
  • -f – go to background just before command execution
  • -N – do not execute a remote command (just forward ports)
  • -L – forward the given port on the local (client) host to the given host and port on the remote side
• Remote port forwarding: ssh -4 -N -f -R '*:remote_port:127.0.0.1:local_port' user@server
  • -R – forward the given port on the remote (server) host to the given host and port on the local side
  • * – the remote server listens on all interfaces (requires GatewayPorts yes in its sshd_config)
  • -4 – use IPv4 addresses only
• SSH VPN tunnel: there is a very good manual on the Ubuntu help pages: SSH_VPN