When I open MSN Messenger, my firewall reports an outbound connection on port 7001 (UDP) by msnmsgr.exe. I have been unable to find out what msnmsgr.exe uses this connection for. MSN Messenger seems to work fine if I block the connection. Does anyone here know what it’s used for?
The callback is needed so you can know when your cached file is updated. The point is that you are absolutely sure when your cache-file is up-to-date. The files are cached locally even when they are not used and they stay in the cache until they get garbage-collected (because of full cache) or until you get a callback.
Although it may appear on the surface that MSN Messanger is working properly with this port blocked, my guess would be that due to the nature of what I have posted above, there IS the possbility that you will have an out of date cache with this program and something COULD go wrong.