[X2go-dev] Port conflict when using x2go client och x2go server

[John A. Sullivan III]

On Sat, 2011-01-15 at 16:34 +0100, Daniel Lindgren wrote:
> Hello.
> 
> I've run into a problem when using x2go to remote control a server
> which in turn remote controls another server using x2go, i.e. client_a
> -> server_a -> server_b.
> 
> I can create the sessions without problem, but I can't reconnect to
> server_a if I suspend the session. I get an error message about "the
> remote proxy closed the connection while negotiating ...".
> 
> As far as I can see there is a port conflict. Ssh on client_a forwards
> local port 30001 to/from sshd on port 30001 on server_a, which in turn
> has an ssh that forwards local port 30001 to/from sshd on port 30001
> on server_b.
> 
> I've worked around it by manually changing SSH_PORT range in
> /usr/bin/x2gostartagent on server_b to start at 30100 (i.e. a
> different range than server_a uses).
> 
> I don''t know the inner workings of all x2go components, but by
> studying x2goclient-cli I'm guessing that separating port ranges to
> use when forwarding would solve it permanently; instead of using
> "30001:localhost:30001" one would use "31001:localhost:30001", thereby
> separating ssh and sshd ports if they are running on the same machine.
<snip>
That's an interesting proposal.  Thanks for tracking it down - John