So it's outgoing connections to port 6346 that don't make it? By default, firewalls don't restrict that port for outgoing connections, so I'd rather look a bit further than the firewall to your Internet provider. Are you on a campus? I noticed a lot of sysadmins at universities are blocking access to the Gnutella ports.

What you can do instead, is find a public HTTP proxy (NOT a SOCKS proxy) and a Gnutella client that supports HTTP proxies. Public HTTP proxies are a bit hard to find, particularly the ones that allow outgoing connections above the 1024 range.

So what does this HTTP proxy solve? Most HTTP proxies listen on port 80 or 443. These two ports are usually open for everyone, because they are the ones you connect to when you visit a regular Website. But instead of being a regular website, you can ask an HTTP proxy to connect to someoene else *for* you. So, you'd connect to a HTTP proxy on port 80, and that proxy will connect to someone else on the given host and port, and thereafter will forward all data back and forth between you.