Open an ssh tunnel between two servers from a 3rd trusted server

Question

Assume I have 3 servers: A,B and C

C can ssh to both A and B but A and B can't connect to eachother.

Is it possible to open a tunnel between A and B using C as in "intermediary" without proxying all my traffic through C ?

Answer 1

If A and B can't connect, then the traffic will have to go through C. You want to run (on A):

ssh -L A:portA:B:portB user@C

While that would usually be run directly on A, perhaps you can run it remotely from C (but I don't have a 3rd machine to check):

ssh user@A "ssh -L A:portA:B:portB user@C"