I connect (via
ssh -Y ...) from a machine (=client) to another machine (=server, actually in my LAN, but it is irrelevant); then I start a new network namespace (NNS, for short) on the server, I start an xterm (from the default namespace) which is displayed perfectly on my client, and lastly, from within the xterm, I join the non-default NNS,
ip netns exec NNSName bash
I can check that I am in the new NNS,
ip netns identify $$
and I can run complex programs like, for instance, OpenVPN from within the new NNS.
The rub is here: I would like to start a graphical application (even just
xeyes, for the moment) from within the new NNS, but I can't, I am always told:
Unable to open DISPLAY=...
Admittedly, I have only tried the obvious:
xhost + on the client, for pure debugging purposes.
I have no problems:
ssh -Y ....from client to server, running
xeyeson the server and displaying it on the client;
starting a new NNS on the server, and starting graphical applications within the NNS to be displayed on the server (i.e., in this case forget about the client).
It is when I put these two things together (ssh and namespace) that I cannot display on the client applications running in the server's new NNS.
It appears the standard TCP port 6010 belongs to the ssh session with the default NNS, while the new NNS ought to get its own. I can surely start an ssh server in the new NNS and connect directly from the client to the server's new NNS, but I was wondering: is there any easier way to do this, i.e. to display graphical applications running in the server's new NNS on the client's X11-server?