Skype is rather good at working with firewalls without the need for any additional configuration, but sometimes it needs some help.
Works with: all versions of Skype.
Many VoIP applications simply don't work from behind a firewall or Network Address Translation (NAT) device. And many, if not most, broadband Internet users operate from behind one or the other, or both!
Skype does a good job of transcending these barriers to communication, mostly without any additional configuration, but Skype is not foolproof in this respect. This hack will help you if you're having problems getting Skype to work from behind a firewall.
Firewall problems are most often signaled by Skype error #1102, "Skype cannot be started;" though #1101, 'No connection," and #1103, 'No connection," are also common. These errors mean that your Internet connection is down or misconfigured, you are behind a restrictive firewall or proxy that is blocking Skype's access to the Internet, or your network or Internet service provider is somehow blocking Skype.
Figure 3-15. Using a Skype server to replace two existing regular phone lines
To learn more about the nature of your Internet connection, and how it might be blocking Skype, you can try these tests:
Are other P2P-type applications also blocked? If the answer is yes, it's more likely that ...