I guess you should somehow configure your connection to keep alive only if there is an OUTGOING request, not an incoming.

After using Gnutella for a while I get about 5 to 10 incoming requests a day for months (even I did not use Gnutella for a long time).

The way your connect is configured even a portscan by some nasty hacker (which just happens from time to time) will keep your connection alive.