I totally concur with f0dder (and Carol), which is the reason I mentioned the IP tables thing. With that you can (dynamically) filter out whatever kind of packets you like from the incoming and/or outgoing traffic.
Although you have to be careful when configuring, it will increase your safety if it is properly setup. The bonus is the traffic shaping, that also reduces the "noise/chatter" on your network.
Personally I have a hard time believing it, but when I copy stuff from my personal system to my linux (samba) backup server using Total copy (explorer extension) it reaches a speed of 12Mbyte/sec through my 100Mbit network. Vice versa it goes to 10.5Mbyte/sec.