Is there a tool that probes a limited internet connection for tunnelling options?

Hey! Is there a tool that can be used to test possible ways to poke through a firewall. Eg install it on a server with direct internet access and the client can then test what methods it can use to reach the server. Eg DNS queries, ICMP request, http requests with special headers etc.

If you don't know of a tool, maybe you can add some methods that could be tried if someone (or I) decides to develop a tool.