Don't use this program any more! It is broken and therefore unusable. Moreover it does not work with Kernels >= 2.4. I suggest using VTUN instead, allthough I have not tested it myself.
This is the homepage of taptunnel, a TCP/IP-application, which allows to create ethernet-tunnels over the Internet or any other TCP/IP-net. It uses the new ethertap-device of the Linux kernel 2.2 and above. (I believe some 2.1-Kernels have it too.) It is not much more than a quick hack, so don't expect too much of it.
It is a single-threaded program, which can be client, stand-alone server and INETD-based-server. There is not much difference between taptunnel acting as server and as client. The connection is encrypted with the routines of the cryptography-library mcrypt-nm of Nikos Mavroyanopoulos. Both hosts need to authenticate itself to the other. This is why two passwords are needed for TapTunnel's work.