i'm trying to find a way to create a GRE Tunnel on osx lion, i'm able to create such tunnels in almost every os, including: openbsd/freebsd, linux and cisco IOS.
I'm very surprised that this subject is not discussed in any related osx threads over knowledge sources, ie. google, forums and QA sites.
I found only a couple questions on forums without answer.
Update: The project at http://code.google.com/p/mac-gre/ has been updated and compiles under 10.8 as of Oct 2012. I just compiled it and installed.