[c-nsp] ARP Timeout - IP address takeover

[Stephen J. Wilcox]

Various systems age arp entries differently.. cisco is quite good at it tho but 
you will need to send out some broadcasts to ensure this happens else the 
devices will continue to use the old mac address until they age out and a new 
arp is sent.

Alternatively as I see someone else suggested you could reconfigure the mac 
address so that whichever machine is active uses that mac. (You'll need to 
figure out how to ensure both arent active at once)

Another nice way is to use a virtual IP (like you are doing) and operate a 
routing protocol on the servers, something simple like rip will do it or you can 
go for a full on quagga install and use ospf which will get failover in seconds 
and avoid any mac conflicts...

Steve

On Fri, 21 Jan 2005, Paul Stewart wrote:

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> Hi there..
> 
> Our mail administrator is implementing a small mail cluster solution
> that involves  using IP takeover techniques in case of failure.  So, at
> one moment an IP could belong to one MAC address but if a box fails that
> IP could showup with a different MAC within seconds....
> 
> Since our core network is 100% Cisco, is there any ARP related issues
> that will delay our customers in seeing the proper MAC if a mail server
> failure should happen?  Or, is there any way to control the default ARP
> timeout for a specific IP address?
> 
> Thanks in advance,
> 
> Paul
> 
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