RE: Filtering Routes in RIP

No i don't mean logical AND. i ment it what i ment it, a logical OR. That is what is happening in reality. I know it is poorly documented and there is confusion about it.

the command below will ALLOW 30.0.0.0/14 from any ROUTE-SOURCE OR It will DENY all routes from ROUTE-SOURCE 155.1.0.4 but allow all other. it doesn't mean that deny 30.0.0.0/14 from ROUTE-SOURCE 155.1.0.4. just lab it up :)

distribute-list prefix ALLOW_SPECIFIC gateway GATEWAY_R4 in Serial0/0

I hope that it will clear things up a bit.

----------------------------------------
> Date: Sun, 21 Aug 2011 23:47:34 -0700
> Subject: Re: Filtering Routes in RIP
> From: yuribank_at_gmail.com
> To: khanzadap_at_hotmail.com
> CC: roy.waterman_at_gmail.com; bxperts_at_gmail.com; ccielab_at_groupstudy.com
>
> Actually, I think you mean to say it is a logical AND operation.
>
> Both conditions must be met. The actual route must match against
> <routeprefixlist>, and the route source must match against
> <gatewayprefixlist>.
>
> So in the OP configuration:
>
> ip prefix-list ALLOW_SPECIFIC
> seq 5 permit 30.0.0.0/14
> seq 10 deny 0.0.0.0/0 le 32
>
> ip prefix-list GATEWAY_R4
> seq 5 deny 155.1.0.4/32
> seq 10 permit 0.0.0.0/0 le 32
>
> router rip
> version 2
> distribute-list prefix ALLOW_SPECIFIC gateway GATEWAY_R4 in Serial0/0
>
>
> This will match: ONLY 30.0.0.0/14 from any source EXCEPT 155.1.0.4/32, for
> Serial0/0
>
>
> -Yuri
>
> On Sun, Aug 21, 2011 at 5:54 PM, sameer khan <khanzadap_at_hotmail.com> wrote:
>
> > That to the best of my understand is incorrect. it will filter out all
> > routes from gateway 155.1.0.4 OR it will only permit 30.0.0.0/14 from any
> > other gateway. As i said before it is Logical OR operation and not logical
> > AND between the two prefix-list used.
> >
> > HTH
> >
> >
> >
> > > From: roy.waterman_at_gmail.com
> > > Date: Sun, 21 Aug 2011 23:15:44 +0100
> > > Subject: Re: Filtering Routes in RIP
> > > To: bxperts_at_gmail.com
> > > CC: ccielab_at_groupstudy.com
> > >
> > > Hi Shahid
> > >
> > > In the case of your config, only the prefix 30.0.0.0/14 will be accepted
> > > from all gateways apart from 155.1.0.4, for updates received on
> > serial0/0.
> > >
> > > Regards
> > > Roy
> > >
> > > On 20 August 2011 22:01, Shahid Mushtaq <bxperts_at_gmail.com> wrote:
> > >
> > > > Dears,
> > > >
> > > >
> > > >
> > > > I want to filter specific routes in RIP from one gateway while allowing
> > > > from
> > > > others.
> > > >
> > > >
> > > >
> > > > If I have the following configuration then how the routes will be
> > treated.
> > > > The distribute-list will only allow "30.0.0.0/14" from all gateways or
> > it
> > > > will be only specific to "155.1.0.4" gateway.
> > > >
> > > >
> > > >
> > > > To more specific, the distribute will go to check the check the prefix
> > then
> > > > the gateway or some other method.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > ip prefix-list ALLOW_SPECIFIC
> > > >
> > > > seq 5 permit 30.0.0.0/14
> > > >
> > > > seq 10 deny 0.0.0.0/0 le 32
> > > >
> > > >
> > > >
> > > > Ip prefix-list GATEWAY_R4
> > > >
> > > > seq 5 deny 155.1.0.4/32
> > > >
> > > > seq 10 permit 0.0.0.0/0 le 32
> > > >
> > > >
> > > >
> > > > Router RIP
> > > >
> > > > Version 2
> > > >
> > > > distribute-list prefix ALLOW_SPECIFIC gateway GATEWAY_R4 in Serial0/0
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Regards,
> > > >
> > > >
> > > >
> > > > Shahid
> > > >
> > > >
> > > > Blogs and organic groups at http://www.ccie.net
> > > >
> > > > _______________________________________________________________________
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> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > --
> > > Regards
> > > Roy
> > >
> > >
> > > Blogs and organic groups at http://www.ccie.net
> > >
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Received on Mon Aug 22 2011 - 11:26:55 ART