I have two machines sitting in different offices.
Machine A is an ubuntu server box which does not have an external IP address, but is connected to the internet.
Machine B is an ubuntu server box which does have an external IP address (and is connected to the internet).
As it stands, machine B cannot ssh into machine A, only the other way around. What I was wondering is is it possible for machine A to setup some sort of tunnel which machine B can then use to connect back to machine A? I only need SSH access, and I only need it from Machine B to Machine A.
Any help on this matter is very much appreciated,