In order for instant messages to get from one computer to another, the firewall must first allow this kind of traffic. Fortunately, the Windows Firewall installed with Service Pack 2 is by default set up to allow this kind of traffic.
When troubleshooting IM communication problems, however, you probably want to eliminate this as a possible cause of the trouble. To do so, follow these steps:
1. | Open the Security Center using either the Control Panel or the System Tray icon. Under the "Manage security settings for:" section, choose Windows Firewall. |
2. | As shown in Figure 12-21, make sure that MSN Messenger is enabled as one of types of traffic the firewall allows through. Figure 12-21. Make sure the Windows Firewall allows IM traffic. |
Additional configuration may be needed if passing IM traffic through a SOHO router. Check your router's documentation for details.