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From: Robert Sander <ml-linux-lartc@epigenomics.com>
To: lartc@vger.kernel.org
Subject: [LARTC] ip route add nexthop dead question
Date: Wed, 30 Jan 2002 09:19:53 +0000	[thread overview]
Message-ID: <marc-lartc-101238241424977@msgid-missing> (raw)

Hi!

The question in short:

I try to add a route over two interfaces with the "nexthop" option to
ip, but one of the gateways is always marked dead. How could that be?

Long story:

I have a testbed setup like the following picture:


                       +-----------------------------+
                   192.168.96.1/24             192.168.96.2/24
                       |                             |
192.168.112.0/20 -- Router A                      Router B --
192.168.64.0/20
                       |                             |
                   192.168.101.9/30            192.168.101.5/30
                       |                             |
                   192.168.101.10 - Router C - 192.168.101.6/30

Router C knows how to find 192.168.64.0/20 and 192.168.112.0/20, so I am
able to either set a route between these two networks over router C or
the direct link between A and B. That works perfectly.
But when I now try to add a route over both connections with equal cost
multipath, one of them is always marked dead.

on router A

ip r a 192.168.64.0/20 \
        nexthop via 192.168.96.2 dev eth1 \
        nexthop via 192.168.101.10 dev eth4

gives

192.168.64.0/20
        nexthop via 192.168.96.2  dev eth1 weight 1
        nexthop via 192.168.101.10  dev eth4 weight 1 dead

and the other way round

ip r a 192.168.64.0/20 \
        nexthop via 192.168.101.10 dev eth4 \
        nexthop via 192.168.96.2 dev eth1

gives

192.168.64.0/20
        nexthop via 192.168.101.10  dev eth4 weight 1
        nexthop via 192.168.96.2  dev eth1 weight 1 dead

Kernel is 2.4.17, all advanced routing options are turned on.
I just learned from
http://lists.nycwireless.net/pipermail/nycwireless/2001q4/001142.html
that equal cost multipath is broken in 2.4.13. Is that still true for 2.4.17?

Greetings
-- 
Robert Sander
Computer Scientist                                       Epigenomics AG
Bioinformatics R&D        www.epigenomics.com         Kastanienallee 24
+493024345330                                              10435 Berlin
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             reply	other threads:[~2002-01-30  9:19 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-01-30  9:19 Robert Sander [this message]
2002-01-30  9:38 ` [LARTC] ip route add nexthop dead question Julian Anastasov

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