From: Fred Ingham (fningham@xxxxxxxxxxxxxxxx)
Date: Fri Mar 29 2002 - 13:46:00 GMT-3
Eric: Your reasoning is correct. When applying a distribution list to
any protocol being redistributed the keyword is "out" from the
redistributed protocol. If OSPF is the target routing protocol make
sure that the "subnets" keyword is used.
An example: Redistributing IGRP into OSPF, 172.16.192.0/24.
172.16.193.0/24, 172.16.194.0/24, and 172.16.195.0/24 originating in the
IGRP domain. Want to have only a single route in the OSPF domain
(extra).
router ospf 1
summary-address 172.16.192.0 255.255.252.0
redistribute igrp 100 subnets
distribute list 1 out igrp 100
router igrp 100
netw 172.16.0.0
access-list 1 permit 172.16.192.0 0.0.3.255
Cheers, Fred.
Eric Lemmons wrote:
>
> Fred,
> Just to make sure I understand why your example works, let me inquire
> further.
> The "distribute-list 1 out rip" command, under the "router ospf 1"
> configuration, is telling the IOS to filter the updates coming IN
> from rip (destined to be sent to the OSPF process), before sending
> them OUT to the ospf process. Is my reasoning correct?
> Thanks, Fred.
> By the way, I recently attended the NMC2 course, and I'm sorry I
> didn't get a chance to meet you when I was there.
> Eric
>
> --- Fred Ingham <fningham@worldnet.att.net> wrote:
> > Paul: To filter the routes use: router ospf 1
> > redistribute rip subnets
> > distribute-list 1 out rip
> > Cheers, Fred.
> >
> > Paul Borghese wrote:
> > >
> > > I have a configuration where I would like to redistribute from
> > RIP to OSPF.
> > > I would prefer to apply a filter to limit my distributions. I am
> > running
> > > RIP on an ethernet interface and OSPF on a serial interface.
> > When I apply
> > > the command:
> > >
> > > router rip
> > > distribute-list 1 out ospf 1
> > >
> > > It filters the RIP updates out the ethernet interface. So the
> > router seems
> > > to ignore the fact that I told it to only filter when
> > redistrbuting into
> > > OSPF and instead filters regular rip updates. Here is some
> > debugging
> > > output:
> > >
> > > Before applying distribute-list 1 out ospf:
> > >
> >
> --------------------------------------------------------------------
> > > 02:24:10: RIP: sending v1 update to 255.255.255.255 via Ethernet0
> > > (190.27.2.3)
> > > 02:24:10: RIP: build update entries
> > > 02:24:10: network 87.0.0.0 metric 7
> > > 02:24:10: network 180.70.0.0 metric 7
> > > 02:24:10: subnet 190.27.1.0 metric 7
> > > 02:24:10: subnet 190.27.10.0 metric 7
> > > 02:24:10: subnet 190.27.11.0 metric 7
> > >
> >
> -------------------------------------------------------------------------
> > >
> > > Notice there are a number of routes being advertised out E0.
> > >
> > > Now I will apply the command:
> > >
> >
> ----------------------------------------------------------------------------
> > > --
> > > R7(config-router)#router rip
> > > R7(config-router)#distribute-list 1 out ospf 1
> > > R7(config-router)#
> > > 02:24:15: RIP: Distribute-list changed: sending triggered update
> > > R7(config-router)#
> > > 02:24:35: RIP: sending v1 update to 255.255.255.255 via Ethernet0
> > > (190.27.2.3)
> > > 02:24:35: RIP: build update entries - suppressing null update
> > >
> >
> ----------------------------------------------------------------------------
> > > --------
> > >
> > > Notice the update did not have any entries. So the command
> > distribute-list
> > > 1 out ospf 1 blocks routes from leaving the ethernet interface.
> > >
> > > Why?
> > >
> > > Paul Borghese
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