I agree with Mr - I think such action would break the network. Let's say you have 3000 hosts online, with only 10% sharing any files (and perhaps even that's being liberal). If search requests weren't passed on to clients without any shared files, that means that the entire network's search routing would be forced upon only 300 clients.

The added search requests (essentially 10x as many) would kill the bandwidth of those people who were sharing... People whose bandwidth was already being used to serve files. A week later, nobody would be sharing files because the "price" to do so would be too high.

I wish I had some suggestions on how to fix the congestion, but I don't. Meanwhile I'll keep playing with redir and ipchains, hoping to find a local solution to the firewall problem...

Shaun