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RE: Secondary interfaces behavior with routing protocols posted 10/31/2002
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Hi Stanford

In order to advertise the secondary address, you need to disable the
split-horizon and then use some filter to prevent route feedback.  It will
work that way.


-----Original Message-----
From: Stanford Wong
To: Sam.MicroGate@xxxxxxxxxxxxxx; ccielab@xxxxxxxxxxxxxx
Sent: 10/31/02 8:03 AM
Subject: Re: Secondary interfaces behavior with routing protocols

here are the basics.

only two routing IP routing protocols operate can
operate off of secondary ips.

BGP - because you can change the source address.
ISIS - because it operates on layer 2

The rest of the stuff RIP, OSPF, EIGRP, and IGRP
doesn't work. Or at least I haven't made it work,
because the routing protocol uses the primary address
to establish relationships.

The only problem you have with secondaries with RIP,
OSPF, EIGRP and IGRP is in order for you to advertise
the secondary address, you need to redistribute
connected.  Then you need to use a route-map or
distribute list to know off the unwanted networks from
being advertised.

Hope this helps....

--- Sam.MicroGate@xxxxxxxxxxxxxx wrote:
> Hello Group,
> Does anyone have a good document that explains the
> behavior of secondary
> interfaces with different routing protocols ( RIP,
> EIGRP, OSPF,...etc) I
> read in several posting that secondary interfaces
> can cause some problems. I
> know some of them but I would like to get your
> input.
> Sam

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