Dan,
My Linux server is multihomed in a similar, altho not identical way. My
internal net is gatewayed by the cable connection and carries etho on the
Linux box while the DSL comes directly into eth1 on Linux with no internal
net. If memory serves me correctly I finally got all the right packets
routed out the right interfaces by setting up the gateways correctly in the
kernel routing table. It was definitely not quick or easy to figure out--I
can dig out the details for you tonight when I'm back home and have access
to the machine internals, if you still need them then.
Jim
----- Original Message -----
From: "Dan Sugalski" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, November 28, 2001 9:49 PM
Subject: [Boston.pm] [OT]Multihoming Linux?
Okay, so with @Home potentially going toes-up soon, I've finally gotten the
push I need to get my home box properly multihomed, and I'm having a heck
of a time.
The short bit is I've a Linux 2.2.19 system with a pair of NICs in it.
eth0's hooked to a cablemodem with an IP address of 24.8.96.48, eth1 to a
DSL line with an IP address of 63.120.19.219. (tuatha.sidhe.org and
redcap.sidhe.org for the curious) Both NICs are up and working, and
accessible from their appropriate LANs. (Yeah, I've two separate network
segments in my apartment. The Geek Force is palpable from miles away... :)
What I want is for packets coming from 24.8.96.48 to go out eth0, and
packets coming from 63.120.19.219 to go out eth1. Nothing fancy, I don't
want load balancing or failover or anything of the sort. (Both IPs are
listed as MX entries for sidhe.org, and both are listed as
nameservers--basically I want my names to always resolve, my mail to get
delivered, and to be able to ssh into the functioning interface if one goes
down, and the rest can be hand-patched)
Unfortunately, this has turned out to be non-trivial.
The standard default route, courtesy of /sbin/route, sends everything out
24.8.96.48 and, while @Home is whacky in so many profound ways, the cable
modem *does* block packets that don't either originate from or are destined
for one of its IP addresses. Which is good from a number of perspectives,
just not this one. /sbin/route, unfortunately, only puts in routes based on
a packet's destination IP address not its source, so it looks like it just
won't do.
iproute2, OTOH, looks like it does have the power to set up source-based
routes, but it beats the heck out of me how to set it up so that it
actually works. All the examples seem to assume that you're routing packets
from other machines not yourself, and my attempts to get it functioning
haven't done much besides black-hole everything. (Which is hardly useful)
So... Help?
Dan
--------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
[EMAIL PROTECTED] have teddy bears and even
teddy bears get drunk
