Please help with some special router/masq configuration !!!

From: Mircea Ciocan (
Date: Sat Mar 04 2000 - 03:25:08 EST

        Hi all,

        This is a message to those ipchains/iproute gurus to help me with a rather peculiar setup
of a network:

        Because we have very few "real" network addresses and a large chain of routers until our
site, I setup a multihomed Linux router in that way:

eth0 - all the Internet addresses that I have.
eth1 - a private C class for masquerading office windoze machines
eth2 - an other private C class for comunicating with the last router in chain, here is the
default gway also a private address.
        The machines with Internet addrs from eth0 all works well and snappy, but...

        the gateway router/box can't get to the Internet.
        the masq net is not working.

        Now, ofcorse that was not too hard to see that all this is because the linux router has a
private default gw, and I can solve the masq net problem putting a card in a machine from
Internet LAN and masq on that address, but I seem to remember that was a trick to mangle
packet headers from a local interface to seem to be originate from an other interface in the
same machine that has a routable address.
        I presume that will take care about the masq also, not only will permit to the router box
to see the Internet, but unfortunately I wasn't able to build the neccesary commands with
ipchains/iproute ( I swere to God that I'll learn that combination in time to see it
changing in 2.4.x kernels :).
        So if anybody see that before and can help me with a 2/3/n ;) liner, I'll be a happy guy
again :).

                Mircea C.
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