RE: BGP - Preventing the AS from advertising local net

Dennis:
What you are doing is that setting the community to NO_ADVERTISE and advertising to BB router.BB router on receiving should not advertise to other peers.
As warner said, filter-list can be use to complete the task.
Regards,Khalid

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> To: ccielab_at_groupstudy.com
> Subject: Re: BGP - Preventing the AS from advertising local net
> From: timothy.warner_at_usbank.com
> Date: Mon, 5 Apr 2010 11:03:06 -0500
>
> Try using the neighbor x.x.x.x prefix-list command. That should allow you
> to filter out just the /24 as long as your prefix-list is written
> correctly.
>
> Also, you may be confusing the no-advertise and no-export
> communities....which I don't think you need to solve that problem anyway.
>
>
>
>
>
>
>
>
> From:
> ccie_ka_at_gmx.de
> To:
> ccielab_at_groupstudy.com
> Date:
> 04/03/2010 10:44 AM
> Subject:
> BGP - Preventing the AS from advertising local net
> Sent by:
> nobody_at_groupstudy.com
>
>
>
> Hi GS,
>
> assume there is one AS with the network 172.16.0.0/24
> Also there are 2 other AS's
>
> What is the best practice to prevent _only_ this network to advertise to
> the BB routers ?
>
> router bgp 33
> neighbor x.x.x.x remote-as 33
> neighbor x.x.x.x send-community both
> neighbor x.x.x.x route-map PREV out
>
> ip prefix-list prevent seq 5 172.16.0.0/24
>
> route-map PREV
> match ip address prefix-list prevent
> set community no-advertise
>
> THis soulution prevent the local net to send to the neighbor..
>
> Right now my problem is I doesn't understand why...;-)
> Because I thought the community no-advertise is send to the _next_ AS and
> prevent the specific prefix to send outr the neighbor AS ?!?!
>
> Please can anyone explain me if this a normal behaviour...
>
> Thanks
>
> Dennis
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Received on Mon Apr 05 2010 - 22:21:28 ART