Re: No BGP Default route-target filter

Scott's right about real life: you can't go around typing it in everywhere
in production as it serves a significant purpose and you'd end up passing
way too many routes to neighboring AS's.

In the lab overconfiguration isn't penalized unless it breaks question
requirements so there are certain sets of commands I choose to configure out
of habit depending on which track I'm doing that do no harm if not required
but I'd prefer not to forget to configure if they happen to be needed. This
is one of them for SP (and RS 4.0).

On 6/4/09 1:25 PM, "Scott Morris" <smorris_at_internetworkexpert.com> wrote:

> While it may not lead to lost points in the lab, I would strongly
> suggest knowing where ARF happens and where it doesn't so that you know
> when to properly use this command!
>
> While it may not cause difficult if used inappropriately in the lab, it
> will absolutely cause issues in real life if you use it too much!
>
>
>
>
> *Scott Morris*, CCIE/x4/ (R&S/ISP-Dial/Security/Service Provider) #4713,
>
> JNCIE-M #153, JNCIS-ER, CISSP, et al.
>
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>
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> Splinter wrote:
>> Guys,
>>
>> makes absolute sense.
>>
>> Jared, if you configure extra commands as a habit, wont one get marked down
>> by the proctor?
>> it would seem one is not sure on where to configure the command or when to
>> use it.
>>
>> Splinter
>>
>> On Thu, Jun 4, 2009 at 6:38 PM, Danshtr <danshtr_at_gmail.com> wrote:
>>
>>
>>> Be default, BGP will accept VPNv4 routes with Ext-Community of route-target
>>> equal to route-targets which local VRFs want to import to their VRF table
>>> (route-target import X:Y). This behavior reduces unused VPNv4 routes in the
>>> router's memory.
>>>
>>> The "no bgp default route-target filter" disables this behavior. It is
>>> often in inter-AS MPLS VPN configurations, where transit routers participate
>>> in the BGP VPNv4 route distribution but do not need to import the routes to
>>> a local VRF tables.
>>> HTH,
>>> Dan
>>>
>>>
>>>
>>> On Thu, Jun 4, 2009 at 7:26 PM, Splinter <splinter330_at_gmail.com> wrote:
>>>
>>>
>>>> Hi All,
>>>>
>>>> need some clarification on the use of the "no bgp default route-target
>>>> filter"
>>>>
>>>> here is my example:
>>>>
>>>> BGP AS 1010
>>>> r4 ---------- r6
>>>> | |
>>>> | FR |
>>>> | |
>>>> | |
>>>> R2-----------R9
>>>> BGP AS 10
>>>>
>>>> R6 - ABC Site 3 RT 1010:10
>>>> R2 - ABC Site 2 RT 10:10
>>>> R9 - XYZ Site 2 RT 1099:10
>>>>
>>>> BGP VPNV4 setup between all routes. To my understanding i only have to
>>>> configure the command
>>>> under the PE routers that will be carry multiple VPNV4 routes. ie the will
>>>> be R2 and R9.
>>>>
>>>> Do i also have to configure it on R4 and R6 as well?
>>>>
>>>> thank you
>>>>
>>>> Splinter
>>>>
>>>>
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Cheers,

Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP
Sr. Technical Instructor - IPexpert, Inc.
URL: http://www.IPexpert.com
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
Mailto: jscrivener_at_ipexpert.com

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Received on Thu Jun 04 2009 - 14:08:55 ART