Adding WCCP support to Linux, transparent/interception proxy

[ATC]

The squid FAQ document http://www.squid-cache.org/Doc/FAQ/FAQ-17.html describes how to set up transparent proxies, but does not go into detail on how to re-compile the modules ip_gre.o and ip_wccp.o in order to make the whole thing work.

[ATC]

The important bit is that BOTH these modules must be compiled, because as of RH7.1 the standard ip_gre module needs to be patched and the ip_wccp module is missing altogether.

To save you some hassle, I have kept the patched files and some other assorted goodies for you. I compiled and ran these on a stock 2.4.2-2smp kernel from Redhat, to make them work on other distros/versions you may have to do some additional tweaking.
My archive can be found here: http://home.atc.no/~floyd/wccp/
(See the local README file for more info)

Another problem we have seen is that the router emits error messages like these:
"1w6d: WCCP-EVNT:: Unknown msg_type 7 on xxxx from x.x.x.x"
"1w6d: WCCP-EVNT:: Unknown msg_type 7 on xxxx from x.x.x.x"

- In "squid.conf", add the config line "wccp_version 3"
- In the router setup, add the line "ip wccp version 1"

If it doesn't work for you, then you may have to figure things out for yourself just like I had to :-/