Hey guys - I just sent an update off to Valve.
The linux dedicated server hasn’t been working for a week or so. The cause of this was a Source ngine update which changed stuff to make way for the linux client version. These changes turned out to be a lot of work to merge into and get compiling on linux, osx and windows. But it’s all done now.
So hopefully this update will allow linux hosts to host again - without causing anyone else any troubles.
Servers will need to be updated and restarted before you will be able to join.