From: Jared Scrivener (jscrivener@ipexpert.com)
Date: Sat Jan 31 2009 - 00:25:18 ARST
Whilst it is true that an OSPF Router ID doesn't have to be pingable, it
generally makes life easier to use a reachable IP (normally Loopback 0).
Let's say that you are asked to also turn on "ip ospf domain-lookup" which
will translate your neighbor's Router-ID into a DNS name (which will either
be defined by a hosts file or received via DNS).
If you do it via hosts entries and your are ALSO a DNS server then your DNS
clients would receive an unreachable IP address when they ping via DNS name.
I know that's a rare case, but given the nature of question interdependency
on the lab (and the evil nature of workbook vendors) I personally use L0 as
my OSPF Router-ID (and set it manually using the "router-id" command) every
time unless otherwise directed.
Cheers,
Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP
Technical Instructor - IPexpert, Inc.
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
Mailto: jscrivener@ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jason Madsen
Sent: Friday, 30 January 2009 9:01 PM
To: ciscozest
Cc: Cisco certification; Cisco certification
Subject: Re: about OSPF router ID
OSPF Router IDs can be any UNIQUE IPv4 address...they don't have to be
addresses assigned to an interface.
On Fri, Jan 30, 2009 at 6:56 PM, ciscozest <ciscozest@gmail.com> wrote:
> Hi all,
>
>
>
> I read Cisco press book stated that OSPF router ID do not need to be
> pingable. In this case if I use a router ID which is not assigned to any
> interface on that router, would this cause any issue such as OSPF
> adjacency,
> LSA table advertisement, etc? Has anyone do this before and can enlighten
> me? Thanks.
>
>
> Blogs and organic groups at http://www.ccie.net
>
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