Version 1.0.1 has an issue with public and private servers for Linux, and the fix is beyond my control as it relies on a 3rd party tool. I am working with them to identify the issue and will have it up and running as soon as possible.
Please note that everything else in the Linux build works properly - full local features, and direct IP connections for online play - and Windows and OS X are unaffected by this. Thanks for your patience. :)