From: Albert Lu (albert_ccie@xxxxxxxxx)
Date: Tue Nov 06 2001 - 05:22:54 GMT-3
Hello Robert,
If the interface is not used in the routing process, then it should not be
passive. For OSPF you can have a higher control on which interfaces you want
to be part of the routing process, so that shouldn't be a problem.
For RIP, IGRP and EIGRP you don't have inverse masks like OSPF (however
EIGRP does seem to have it now, but it seems abit flakey) so you would need
to put passive interfaces for the interfaces that shouldn't be sending any
updates. However this doesn't mean that the routing process stops running on
the interface, because it still considers it part of its routing process.
This is important as sometimes you have OSPF running on some interfaces and
RIP/IGRP/EIGRP on other interfaces on one router, eventhough you specified
passive interface for the RIP/IGRP/EIGRP. Route flaps on the OSPF interface
will also cause RIP/IGRP/EIGRP think that one of it's interface is flapping
and send out updates. A solution to this would be distribute-lists or
route-maps to filter the distribution between the two routing protocols.
You would also notice that diagrams specify what coverage each routing
protocol would have, so if the diagram's RIP coverage was only for one
interface, then RIP should only come out of that interface.
Albert
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
McCallum, Robert
Sent: Wednesday, October 31, 2001 9:52 PM
To: 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail)
Subject: To Passive or Not to Passive
Dear all,
Before I take the leap into the lab (2 weeks to go now), I have a question
which has dogged me for a while now. Scenario below.
Router 1 has the following interfaces, Lo0, Eth0/0, S0/0, S0/1 and say
Fast0/1.
Router 2 has the following interfaces Lo0, Lo1, Eth 0/1, S0/0.
Between Router 1 (s0/0) and Router 2 (s0/0) we are running say OSPF. On
router 1 (e0/0 and s0/1) we are running RIP.
On Router 2 (e0/1 and lo1) we are also running Rip.
Router 1 (lo0, s0/1) and Router 2 (lo0) are running Eigrp.
Now for the questions
1. On router 1 OSPF process is running Q: should I put lo0,e0/0, fast0/1
and s0/1 as passive interface ??? This worries me quite a bit as the
argument of if you dont put the network command under ospf then ospf will
not run on that interface...BUT I have been told that you should ALWAYS put
every
"in use" interface into passive if it is not being used under the routing
process.
2. This is not a question but a sanity check that for EIGRP and RIP then
the "norm" rules of passive interfaces apply.
Thanks for anyones help in clearing this annoying matter up.
Robert McCallum
Ext 730 3448
DDI : 01415663448
Mobile : 07818002241
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