From: click here
Norton Internet Security 2003 or later and Norton Personal Firewall 2003 or later:
1. Start the Norton Internet Security or Norton Personal Firewall program.
2. Click Personal Firewall, and then click Configure.
3. Click the Programs tab.
4. Remove all the instances of Msnmsgr.exe from the Manual Program Control List.
5. To add MSN Messenger to the list, click Add.
6. Double-click the Msnmsgr file.
7. Make sure that the Msnmsgr file is added to the Programs and Services list and that MSN Messenger is selected.
8. Make sure that the file is added to the Manual Program Control List
9. In the Internet Access column, make sure that MSN Messenger is set to Permit All
10. For more information, refer to the Norton knowledge base , select the version of the product that you are using, and then search for “Changing Internet Access Control settings” or “Changing firewall rule settings“ in the product manuals.
All other versions of Norton:
1. Visit the Norton knowledge base , and then look for “Changing Internet Access Control settings” or “Changing firewall rule settings “ in the product manuals.