Re: EIGRP Distribute-list with Gateway command

Hi Carlos,

Well .. while trying to get my head round this issue , I tried the same
config in a setup when R1 has two different ethernet interfaces connected to
R2 and R3 i.e R1 F0/0 connects to R2 and R1 F1/0 connects to R3 . The same
prefix-list statements and distribute-list works just as expected in that
scenario . I would assume the same mechanism would be applied in this
scenario as well ..

Regards,
Ravi

On Tue, Feb 8, 2011 at 11:11 AM, Carlos G Mendioroz <tron_at_huapi.ba.ar>wrote:

> Ravi,
> updates have to PASS the filter. When you put prefix and gateway
> conditions, they have to pass both.
>
> So in your first config, no route passes the prefix, it does not matter
> where it comes from.
>
> -Carlos
>
> Ravi Singh @ 08/02/2011 01:52 -0300 dixit:
>
>> Hello Group ,
>>
>> The below email might seem long in the first glance but it is a simple
>> question with a very simple setup .
>>
>> R1
>> |
>> |
>> ------------------SW
>> | |
>> | |
>> R2 R3
>>
>> If wordwrap ruins the art, the setup is F0/0 on R1, R2 and R3 each is
>> connected to a common LAN segment through SW1. The IP Addresses on the
>> F0/0
>> interfaces are 10.1.1.1/24, 10.1.1.2/24 and 10.1.1.3/24 respectively. R2
>> and
>> R3 both have the same Loop 1, Loop 2 and Loop 3 addresses which are
>> 1.1.1.1/24, 2.2.2.2/24 and 3.3.3.3/24 respectively.
>>
>> R1, R2 and R3 run EIGRP between them. Here is the routing table on R1
>> under
>> normal circumstances
>>
>> R1#sh ip route eigrp
>> 1.0.0.0/24 is subnetted, 1 subnets
>> D 1.1.1.0 [90/156160] via 10.1.1.3, 00:00:03, FastEthernet0/0
>> [90/156160] via 10.1.1.2, 00:00:03, FastEthernet0/0
>> 2.0.0.0/24 is subnetted, 1 subnets
>> D 2.2.2.0 [90/156160] via 10.1.1.3, 00:00:03, FastEthernet0/0
>> [90/156160] via 10.1.1.2, 00:00:03, FastEthernet0/0
>> 3.0.0.0/24 is subnetted, 1 subnets
>> D 3.3.3.0 [90/156160] via 10.1.1.3, 00:00:03, FastEthernet0/0
>> [90/156160] via 10.1.1.2, 00:00:03, FastEthernet0/0
>>
>> Now the objective (and the issue ) - I want to configure distribute-list
>> using prefix-lists on R1 to *DENY* everything that *COMES* from R3 ( bold
>> keywords just to stress on logic )
>>
>> So here are the two prefix-lists that I made
>>
>> ip prefix-list DENY-ALL seq 5 deny 0.0.0.0/0 le 32
>> !
>> ip prefix-list FROM-R3 seq 5 permit 10.1.1.3/32
>> !
>>
>> And then I used the below command to achieve what is being expected
>> router eigrp 100
>> distribute-list prefix DENY-ALL gateway FROM-R3 in FastEthernet0/0
>>
>> The output on R1 now becomes
>>
>> R1#sh ip route eigrp
>>
>> R1#
>>
>> Basically no routes. So it denies everything coming in F0/0, even though I
>> specified the gateway. BUT , if I change the logic i.e *PERMIT* everything
>> that does *NOT* come from R3 , it works just fine . Therefore If I make
>> the
>> prefix-lists as
>>
>> ip prefix-list NOT-FROM-R3 seq 5 deny 10.1.1.3/32
>> ip prefix-list NOT-FROM-R3 seq 10 permit 0.0.0.0/0 le 32
>> !
>> ip prefix-list PERMIT-ALL seq 5 permit 0.0.0.0/0 le 32
>>
>> And the distribute-list as
>>
>> router eigrp 100
>> distribute-list prefix PERMIT-ALL gateway NOT-FROM-R3 in FastEthernet0/0
>>
>> The output on R1 is as expected now .
>>
>> R1#sh ip route eigrp
>> 1.0.0.0/24 is subnetted, 1 subnets
>> D 1.1.1.0 [90/156160] via 10.1.1.2, 00:02:01, FastEthernet0/0
>> 2.0.0.0/24 is subnetted, 1 subnets
>> D 2.2.2.0 [90/156160] via 10.1.1.2, 00:02:01, FastEthernet0/0
>> 3.0.0.0/24 is subnetted, 1 subnets
>> D 3.3.3.0 [90/156160] via 10.1.1.2, 00:02:01, FastEthernet0/0
>> R1#
>>
>> So, the question is What am I doing wrong in the first method ? Are there
>> some basic rules that are being broken here ?
>>
>> Regards,
>> Ravi
>>
>>
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>>
> --
> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina

Blogs and organic groups at http://www.ccie.net
Received on Tue Feb 08 2011 - 11:21:40 ART