Unused port blocking from other home computer

Hello,

 

I'm using NIS 2009 and the following is noted in the recent history 6-8 times over a 4 hour period:

 

Unused port blocking has blocked communications.

Inbound TCP connection.

Remote address, local service is (64.180.XX.XXX, Port http-proxy(8080) ).

 

This address is the IP address of my other home computer. Both computers are connected to a single ADSL line through a switch.

 

Is this normal?

 

Thanks in advance for any advice.