Blocking Skype with OpenDNS
At this time, Skype cannot be blocked by simply blocking a domain. Unfortunately, this means Skype cannot be blocked using OpenDNS's domain block lists. Skype utilizes a large repository of IP addresses in order to connect to the main service.
Blocking certain Skype domains may result in lost functionality or inability to download the application from Skype.com, but the service itself will connect and run.
A popular post on PingTool.org describes blocking all of Skype's IP addresses on a computer, firewall, or router. However, this method may not have a perfect success rate and OpenDNS is unable to support this in any way.