So I've struggled with this at points, even when running SL on the one machine (localhost vs hostname).
My current looping setup requires sooperlooper engine on one PC and Slgui on another. I've connected them both together with a crossover cable and have confirmed connectivity is fine but neither slconsole or slgui can connect to the engine, no matter if I specify hostnames (valid) or IP addresses.
I've confirmed that OSC is performing correctly, as my test OSC program connects fine via the crossover cable - so the issue is definitely in SL.
I've seen jesse remark that the networking code in SL is flaky - I'd really like to get this fixed, can happily edit and recompile if I know where to look.
Does anyone currently have SL on multiple devices working under Linux?