IPfwd: an IP protocol redirection tool

The current version of IPfwd is 1.0.0.

IPfwd is free software, licensed under the terms of the GPL. See the file COPYING for details.

Previous versions of IPfwd and RPM format distributions can be found in the file archive.

What is IPfwd?

IPfwd is a tool to perform redirection of arbitrary IP protocol datagrams. This is useful for implementing Firewalls and IP Masquerading, among other things. Another tool you might wish to look at is redir (RPM) which redirects TCP/UDP sockets.

IPfwd was originally written to support gatewaying PPTP (Internet Draft) across a linux-based firewall. IPfwd uses TCP port 1723 and IP protocol 47. Other tools, including redir and portfwd can be used to redirect PPTP across the firewall, but there were no tools to handle the IP protocol 47 datagrams. IPfwd is the solution, and is currently in production use.

IPfwd should (must) be used in conjunction with support for outgoing PPTP masquerading. See http://www.wolfenet.com/~jhardin and http://bmrc.berkeley.edu/people/chaffee/linux_pptp.html for ways to do this. I personally use John Hardin's patch set.
Ignore his claim that his patchset is not necessary for PPTP server masquerading.

Bug reports, patches, and suggestions should be sent to cananian alumni.princeton.edu.

cscott cscott.net