SSH Tunnels (Linux)
ssh -N localhost -L localport:remotemachine:remoteport -f
Setup an SSH tunnel on the localhost and taking connections from port 3335 and forwarding them onto port 3306 on a remote machine db02:
ssh -N localhost -L 3335:db02:3306 -f
This is fairly simple but not that useful as it will only work within in a network. If a remote SSH server is used then a SSH tunnel can be used to allow a connection between two separate networks; over a WAN for example.
ssh -pnon-standard-port -N remotesshserver -L localinterface:localport:remotemachine:remoteport -f
If the remotesshserver does not listen on the standard port of 22 it must be specified in -pnon-standard-port; otherwise it can be omitted.
Setup SSH tunnel using a remote ssh server perimeterssh01 on where SSH listens on a custom port 2400, taking connections from port 6000 on a specific local interface of 127.0.0.2 and forwarding them onto port 6002 on remote server 10.10.8.50 within the remote network of perimeterssh01.
ssh -p2400 -N perimeterssh01 -L 127.0.0.2:6000:10.10.8.50:6002