[Full-disclosure] Blocking Skype on ISP level

[AH AH]

Some ISPs are blocking Skype traffic on their networks, does anyone
know how did they succeed in doing that? as per the analysis done on
the skype peer to peer internet telephony protocol paper
http://arxiv.org/ftp/cs/papers/0412/0412017.pdf
Skype still succeeds in bypassing  firewalls and NAT devices, i would
like to have the public feedback on the best ways to block it on the
ISP level.

xmxl