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Welche Ports bei TCP bzw. UDP Verwendet eigentlich Skype?

The minimum requirement is that Skype needs unrestricted outgoing TCP access to all destination ports above 1024 or to ports 80 and 443 (the former is better, however). ...

In the quest for even better voice quality, it is also advisable to open up incoming TCP and/or UDP to the specific port you see in Skype Options. This port is chosen randomly when you install Skype.

http://www.skype.com/help/faq/technical.html