You are talking about personal firewalls, here. The term 'firewall' also applies for routers which can serve e.g. as a proxy between the internet and a LAN.

The problem with node behind a router is that it won't accept incoming packets without setting up port forwarding. NAT means "Network Address Translation" (same as IP Masquerading for *n*x users). On a LAN you would be sending packets meant for some host outside you LAN to your router. Your router will disassemble that packet and exchange your local IP address for the router IP address on the internet. However, if the router receives a packet from the internet, it does not know where to send it on the LAN, unless you set up the router to forward all incoming packets e.g. with a certain destination port to you. If you are using a router without NAT, you will not be able connect to gnutella.

Come on, don't act like you knew what NAT is.

PUSH REQUEST ALSO WORK WHEN THE CORRECT IP IS NOT FORCED! I DID READ YOUR POST AND YOU SIMPLY DON'T GET HOW PUSH WORKS!

It's not a safe bet. The vast majority of really fast connections (T1, T3+) are from schools, universities and from work locations. Blocking them is just stupid.

I don't think this discussion is leading anywhere. If you don't believe me that your "advice" doesn't improve anything it's okay with me - I mean you are LeeWare, you're helping people, you're the master of the universe - but still you don't have a clue about the way the gnutella network or the internet in general works. So please, don't try to explain them to others.