Re: [lvs-users] Cisco routers dynamic ARP caching

To: " users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] Cisco routers dynamic ARP caching
From: Joseph Mack NA3T <jmack@xxxxxxxx>
Date: Wed, 12 Sep 2007 16:46:39 -0700 (PDT)
On Wed, 12 Sep 2007, Antonio Anderson M. de Souza wrote:

> Dear All,

> We faced with the same problem described by the original 
post from *Greg
Woods* woods at
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.

Hi Antonio
        Thanks for the update.

        I don't understand the result of your cure. When the 
router asks "who has VIP, tell router" what do the 
realservers reply?

> I knew that this post is really old, and probably *Greg 
Woods* woods at<>already
solved his problem, i am only sending this post to share our
experience with others LVS users.

Never too late to fill gaps in our knowledge

Thanks Joe

Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at
Homepage It's GNU/Linux!

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