[zx2c4]

I think sshuttle is pretty cool. It does layer 3 tunneling over TCP in the right way. Usually when VPNs (like OpenVPN) try to tunnel IP packets over TCP, if those IP packets contain TCP data itself, then you have this problem with tunneling TCP over TCP, and the rate and congestion control algorithms of the two instances of TCP step all over each other, and performance becomes miserable. But sshuttle has done something pretty neat to fix that: it actually parses the TCP in the packets it receives, reconstructs those packets into a normal byte stream, and then sends that over TCP, reflowed, to then be converted back into the original TCP stream on the other end. It's a tiny bit involved, but they made it work well, and most of the time sshuttle "just works."

[beagle3]

Indeed. It even has (or at least had in previous versions) a configurable ping-time monitor that traded some bandwidth for interactivity - which is another part of what makes it work so well.