[LARTC] Split access multi-route problem - need help.

From: Mike Harris <mike@psand.net>
To: lartc@vger.kernel.org
Subject: [LARTC] Split access multi-route problem - need help.
Date: Wed, 21 Nov 2007 14:08:01 +0000	[thread overview]
Message-ID: <47443BC1.4060001@psand.net> (raw)

Hello,

Am writing to the list in the hope that someone out there might be able
to shed some light on a weird problem I have with a multiple route
configuration.

Some time ago I configured a web server to have two different IP
addresses from two different ranges on each of it's two ethernet cards.
 I followed the excellent instructions at
http://lartc.org/lartc.html#AEN268 and came up with the following
configuration:

#!/bin/bash
/sbin/ip route add 194.164.97.0 dev eth0 src 194.164.97.252 table T1
/sbin/ip route add default via 194.164.97.1 table T1
/sbin/ip route add 86.54.82.144 dev eth1 src 86.54.82.146 table T2
/sbin/ip route add default via 86.54.82.145 table T2

/sbin/ip route add 194.164.97.0 dev eth0 src 194.164.97.252
/sbin/ip route add 86.54.82.144 dev eth1 src 86.54.82.146

/sbin/ip route add default via 194.164.97.1

/sbin/ip rule add from 194.164.97.252 table T1
/sbin/ip rule add from 86.54.82.146 table T2
/sbin/iptables-save

I'm uncertain if the last line is actually needed there.

Anyway, this worked perfectly, or seemed to.  The two web sites could be
accessed properly and I could use ping to access the internet via either
interface, so 'ping -I eth0 lartc.org' and 'ping -I eth1 lartc.org' both
worked absolutely fine.

Now what's gone wrong.  My lovely web server's RAID controller started
failing and I have to move to another server in somewhat of a hurry.  I
copied over the configuration but on the new server it just doesn't work.

What happens is that whichever interface is defined in the '/sbin/ip
route add default via 194.164.97.1' line of the configuration above
becomes the only route out that works.  So for example 'ping -I eth1
lartc.org' no longer returns a result.

Would appreciate any help, especially if someone can confirm that my
configuration is correct and perhaps shed some light on other things
that I may have overlooked, such as the correct kernel modules etc.

For reference the install is Debian Etch, kernel 2.6.18-5-amd64.

Any help much appreciated,

Thanks in advance,

Mike.
-- 
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Mike Harris
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