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[lvs-users] Cisco routers dynamic ARP caching

To: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Subject: [lvs-users] Cisco routers dynamic ARP caching
From: "Antonio Anderson M. de Souza" <antonioams@xxxxxxxxx>
Date: Wed, 12 Sep 2007 19:06:14 -0300
Dear All,

We faced with the same problem described by the original post from *Greg
Woods* woods at ucar.edu
<lvs-users%40linuxvirtualserver.org?Subject=Re:%20Cisco%20routers%20dynamic%20ARP%20caching&In-Reply-To=%3C200208021715.g72HFQD11154%40mailman.ucar.edu%3E>,
and the short answer is yes, the Cisco Router makes dynamic arp caching, in
our case the Cisco Router are using the arp request sent by the Directors
machine to update the mac address of the vip in the router arp table, this
were happening because the arp request was being sent with VIP as the source
address of the arp request packet.

To solve this issue we change the net.ipv4.conf.all.arp_announce and
net.ipv4.conf.bond0.arp_announce (bond0 is the interface in use) parameter
to value 2 in the /etc/sysctl.conf configuration file [1], this
configuration change the behaviour of all arp request sent by the machine,
the source ip address in the arp request is sent  as the RIP instead of VIP,
in our case this prevent the Cisco Router to update VIP arp table entry.

I knew that this post is really old, and probably *Greg Woods* woods at
ucar.edu<lvs-users%40linuxvirtualserver.org?Subject=Re:%20Cisco%20routers%20dynamic%20ARP%20caching&In-Reply-To=%3C200208021715.g72HFQD11154%40mailman.ucar.edu%3E>already
solved his problem, i am only sending this post to share our
experience with others LVS users.

References
[1] -
http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/LVS-HOWTO.arp_problem.html#2_6_arp_announce

Best regards,

-- 
Antonio Anderson M. Souza
Project Manager
Voice Technology
Rua: Libero Badaró, 293
Cj 30D - 30o. andar
CEP: 01009-907
antonio@xxxxxxxxxxxxxxxxxxxxxx
phone:  +55 11 3588-0188
mobile: +55 11 8224-2756

-- 
Antonio Anderson M. Souza
Project Manager
Voice Technology
Rua: Libero Badaró, 293
Cj 30D - 30o. andar
CEP: 01009-907
antonio@xxxxxxxxxxxxxxxxxxxxxx
phone:  +55 11 3588-0188
mobile: +55 11 8224-2756
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