[c-nsp] Virtual IP Question

[Frank Bulk - iNAME]

I have this one set of appliances -- I added to the failover script a ping
the important devices in the same L2 network.  Works like a charm.

Frank

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of David Coulson
Sent: Thursday, April 10, 2008 8:03 PM
To: Paul Stewart
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Virtual IP Question

Usually when IP takeover occurs, the new 'active' node will send out an
ARP update message to force all devices on the broadcast domain to
update their ARP table. I've run this type of failover (as opposed to a
'virtual MAC') with good success in a variety of configurations.
Especially if you are only routing to this environment, having fast ARP
timeouts can often clear out any split brain problems pretty quickly.

What are the symptoms you see when the problems occur? Incorrect ARP
entry in the switches (I assume these handle VLAN routing too?), bad
entry in the CAM table, or something else?

Your problem implementing something at the network layer may be that the
virtual IP will not be available on both nodes, so if you try to
override the failover functionality, it may not behave as expected.

Paul Stewart wrote:
> Each server is connected to a 6509 switch, on the same VLAN and IP subnet.
> The problem is that the virtual IP representing what people connect to is
> taking over the MAC address of the Ethernet card versus having it's own
MAC
> that stays consistent from server to server (as HSRP does with it's active
> IP - MAC never changes for that IP).
>
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