Re: Filtering Routes in RIP

Dear Sameer,

Thank you for the comments.

I labbed the scenario and noticed that it is using OR with prefix and gateway as u mentioned also.

I think if lab says to block routes from specific gateway then we can use extended access-list in RIP.

Regards,

Shahid

Sent from my iPhone

On Aug 22, 2011, at 2:26 PM, sameer khan <khanzadap_at_hotmail.com> wrote:

>
> 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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>>>
>>>
>>> Blogs and organic groups at http://www.ccie.net
>>>
>>> _______________________________________________________________________
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>>
>>
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>>
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Received on Mon Aug 22 2011 - 17:55:01 ART