To set up SSH tunneling on a Linux, Unix, or BSD server to bypass NAT (Network Address Translation), you will need to have a server with a publicly accessible IP address and an SSH server running on it.
SSH tunneling allows you to create a secure, encrypted connection between a client and a server and use it to forward traffic through the connection. This can be useful in situations where the client is behind a NAT device and cannot directly access the server.
To set up an SSH tunnel, you will need to use the ssh command with the -L option to specify the local port and the remote port and host.
For example, to create a tunnel that forwards traffic from the client's local port 1234 to the server's port 22, you can use the following command:
ssh -L 1234:localhost:22 user@server
This will create a tunnel that allows the client to access the server's SSH service on port 1234. To connect to the server using the tunnel, the client can use the ssh command to connect to localhost on port 1234.
ssh user@localhost -p 1234
You can also use the -N option to run the ssh command in the background and keep the tunnel open:
ssh -L 1234:localhost:22 -N user@server