I was wondering what was causing IP Address 192.168.1.255 to be blocked by the Avast firewall three to four times a second. After doing some searching I found out the problem was caused by NETBIOS being enabled by default in Windows 7.
I turned it off and 90% of my firewall entries went away. Its a lot smaller now, and easier to look through.
This works for me because I don't have a home network, or use printer and file sharing. If you do have a home network and have printer and file sharing, I wouldn't turn it off, unless you just want to experiment and see if your network can function with out NETBIOS.
Here is a link that will show you how to disable it.
http://marjanrepic.wordpress.com/2011/07/05/disable-netbios-over-tcpip-in-windows-7-ent/
