For example I am running Avast firewall/virus program on my old XP system and I wasn’t having any trouble accessing the Vista system because the Networking wizard set all accesses for that system. However, even though the Vista system could “see” the XP computer it could not access anything. The first thing I did was shut down Avast on the XP puter and everything was just fine. Then I went to Avast help documents and found how to add a device/IP to the accepted list.
And because the router was the device that was technically trying to access the Xp system, I used the router address.