Setup SSH reverse tunnel

Aim

We have PC A, PC B.

PC A is behind Proxy and we cannot change any setting about the network, PC B is behind NAT.

We want to use ssh to connect from B to A, so we need to make a reverse tunnel from A to B.

Assume you have setup the openssh server on PC B.

On PC A

$ ssh -R12345:localhost:22 <PC B userName>@<PC B ip> -p <PC B ssh server port> -i <PC B user private key>

• The above command will connect remote port 12345 to local port 22
• If you can connect to PC B, then

On PC B

$ ssh <PC B userName>@localhost -p 12345 -X

• We now connected to PC A from B with x11 supported

Local port binding

ssh -Llocalhost:8888:[target IP]:[target port] -i [private key] [target user name]@[target IP]