Re: Router stops routing after changing MAC Address

From: Stephen Hemminger
Date: Fri Mar 10 2006 - 19:37:37 EST


On Fri, 10 Mar 2006 18:33:15 -0600
"Greg Scott" <GregScott@xxxxxxxxxxxxxxxxxxx> wrote:

> Hello - This feels like a kernel issue. I spent hours and hours and
> hours looking for documentation and archives around this but did not
> find anything.
>
> I have a Linux router and I need the ability to swap hardware without
> causing downtime. The problem, of course, is ARPs. The NICs in the
> replacement system need the same MAC Addresses as the NICs in the
> original system. I'd like this all to be in the kernel and not depend
> on a daemon process that can die.
>
> How to change MAC addresses is documented well enough - and it works -
> but when I change MAC addresses, my router stops routing. From the
> router, I can see the systems on both sides - but the router just
> refuses to forward packets. Here are my little test scripts to change
> MAC Addresses.

You probably just need to flush the route cache after the address change?
-
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