From: OhioHondo (ohiohondo@columbus.rr.com)
Date: Sun Dec 22 2002 - 14:02:36 GMT-3
Sage
You applied the distribute list on R2 preventing the OSPF process on R2 from
putting the update in R2's IP routing table. The Dykstra algorithm on all
three routers, working off of the same LSDB, will come up with the undesired
route to put in the IP routing table. The "distribute-list" command on the
R2 router denies this route from being in R2's routing table.
When the OSPF process (Dykstra) on the other routers runs it does not have
any "trigger" configured to tell it not to put that update in the IP routing
table.
Assuming that all of the routers are in the same OSPF area, and knowing that
the OSPF LSDB is the same on all routers in the same area, I believe that
you have to define the distribute list on every router ( a trigger to modify
Dykstra) where you don't want the route to appear.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Sage Vadi
Sent: Sunday, December 22, 2002 5:20 AM
To: ccielab@groupstudy.com
Subject: OSPF: distribute-lists
This is what CCO says:
Q: Can I use the distribute-list in/out command with
OSPF to filter routes?
A: OSPF routes can't be filtered from entering the
OSPF database. The distribute-list in command only
filters routes from entering the routing table, but it
doesn't prevent link-state packets from being
propagated.
~~~ MY PROBLEM ~~~
Diagram:
R1
|
R2--R3
R1 learns 160.160.0.0/22 from R2, R2 learns this from
R3. Fairly simple right?
I want to put a distribute-list inbound on R2's serial
interface to prevent R1 from learning this
route/network.
Config on R2 here:
distribute-list 108 in Serial1/0
access-list 108 deny ip 160.160.0.0 0.0.3.255 any
Problem:
R1 still has the route in it's routing table!!! Doh!
CCO says it should not be in the routing table, but it
should be in the OSPF database.
Q) Any tips/help/suggestions?
rgds,
Sage
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