Docs > services > ssh_forwarding

Remote forwarding

The following command will make the port 2000 on the localhost accessible on the port 1000 on the example.com.

Note that -nNT prevent the allocation of tty and will just perform port forwarding.

ssh -nNT -R 1000:localhost:2000 user@example.com

Allow the remote host to forward

On the example.com run the following to add "GatewayPorts yes" to the sshd config.

sudo cp /etc/ssh/sshd_config /etc/ssh/sshd_config.orig
echo "GatewayPorts yes" | sudo tee -a /etc/ssh/sshd_config
sudo service ssh restart

Local forwarding

The following command will make the local port 9000 on localhost return port 80 from google.com by using an encrypted connection via example.com

ssh -L 9000:google.com:80 user@example.com

Advanced

Using Server keep alive

Note this is an encrypted packet that cannot be spoofed, unlike tcp keep alive.

-o ServerAliveInterval=60 -o ServerAliveCountMax=3

Using a master socket

Starting

ssh -S <socket-name> -fnNTM -R <remote-port>:<local-ip>:<local-port> <user>@<remote-ip>

Status

ssh -S <socket-name> -O check <user>@<remote-ip>

Stop

ssh -S <socket-name> -O stop <user>@<remote-ip>