I am not sure if I'm looking at a network problem or a bug here. Since the update to 188.8.131.52 my Skype can't connect any more. My room-mate has the same problem. We're both on Ubuntu Raring Ringtail 13.04 on an EliteBook 9470m in my case. Does anyone have the same problem, or do you know of a bug-report?
(Update: Turns out it's neither a bug nor a network problem. Tor exit-nodes are blocked by Microsoft. See my answer below!)
Both purge-reinstall (including the removal of
~/.Skype) and using the .deb from skype.com (version 184.108.40.206_1) instead of the repositories did not help. Running Skype from the command line did not give additional messages.
I don't know how to decode the log files in
~/.Skype/Logs but the usual logs in
/var/log/ show no anomalies. Changing the port Skype uses to one that is forwarded to my machine by the router, did not work either. Nor did running Skype as root.
The fact that I can get it running on the same machine, when I use tethered connection of my mobile points towards a network problem, but then again other machines in our household have no problem at all and I didn't change any network configurations for half a year.