Re: prefix and acl

Thanks all,

John I am just playing with prefix and access-lists. I was inspiried
by some WB I am doing.
I did find this exercise in Narbiks free workbook (Soup to nuts) its
available via Micronicstraning
I was week on prefix-list before but not now :)

Then I did extend this exercises and was thinking, how far can a ACL
or Extended ACL take me.
Can I solve this with one liner ACL standard or extended. Pushing the
limits. I was playing around.

Daniel and Sarad thanks.

Topology

R1---------------R2

Router 2 recive following from R1 via RIP, I have filter those routes
with different prefix-lists,

Ex, only permit A network that are not subnetted.
ip prefix-list 0.0.0.0/1 ge 8 le 8

Ex, only permit B network that are not subnetted.
ip prefix-list 128.0.0.0/2 ge 16 le 16

Ex, only permit C network that are not subnetted.
ip prefix-list 192.0.0.0/3 ge 24 le 24

Ex, only permit A network that are or are not subnetted.
ip prefix-list 0.0.0.0/1 ge 8 le 16

etc..

All route received from R1 via RIP

R2# show ip rou rip
R 1.0.0.0/8 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 2.0.0.0/8 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 3.0.0.0/8 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 223.1.1.0/24 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
     4.0.0.0/16 is subnetted, 1 subnets
R 4.4.0.0 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 191.1.0.0/16 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
     5.0.0.0/24 is subnetted, 1 subnets
R 5.5.5.0 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 200.1.1.0/24 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
     6.0.0.0/26 is subnetted, 1 subnets
R 6.6.6.0 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 128.1.0.0/16 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 125.0.0.0/8 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 131.1.0.0/16 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
     193.1.1.0/25 is subnetted, 1 subnets
R 193.1.1.0 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
     132.1.0.0/24 is subnetted, 1 subnets
R 132.1.1.0 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 192.1.1.0/24 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
     133.1.0.0/25 is subnetted, 1 subnets
R 133.1.1.0 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
R 195.1.1.0/24 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
     194.1.1.0/26 is subnetted, 1 subnets
R 194.1.1.0 [120/1] via 10.1.12.1, 00:00:10, FastEthernet0/0

//Thanks.

2012/6/24 john matijevic <john.matijevic_at_gmail.com>:
> Good Afternoon,
>
> "Can I do this with an acl or extended cal, I have a Brain Freeze
> Thanks."
>
> What is this?
>
> Very vague, can you please be more specific and describe exactly the
> issue or problem that you are trying to solve?
>
> Please post network diagram and configurations.
>
>
> Regards,
> John
>
>
> On 6/24/12, Sarad <tosara_at_gmail.com> wrote:
>> Hi Hasse,
>>
>> We can use a extended access-list in BGP to replace a prefix-list, But in
>> IGP it appears differently as extended accesslist represent the route
>> source and subnet (not subnet and subnet mask)
>>
>> Have a look at this
>> http://blog.internetworkexpert.com/2008/01/04/using-extended-access-lists-in-a-distribute-list/
>>
>> Cheers
>> Sara
>>
>>
>>
>> On Sun, Jun 24, 2012 at 11:12 PM, <daniel.dib_at_reaper.nu> wrote:
>>
>>> Hi Hasse,
>>>
>>> You are trying to match every class C address with /24 mask right? This
>>> is
>>> not possible with a standard ACL. If you used extended ACL you could
>>> match
>>> mask like this.
>>>
>>> access-list 100 permit 192.0.0.0 31.255.255.255 host 255.255.255.0
>>>
>>> However I think this is only supported in BGP.
>>>
>>> /Daniel
>>>
>>>
>>> On Sun, 24 Jun 2012 14:02:01 +0200, Hasse wrote:
>>>
>>>> Can I do this with an acl or extended cal, I have a Brain Freeze
>>>> Thanks.
>>>>
>>>> R2#show run | sec rip
>>>> router rip
>>>> version 2
>>>> network 10.0.0.0
>>>> distribute-list prefix 1 in FastEthernet0/0
>>>> no auto-summary
>>>>
>>>> R2#show run | sec prefix-list
>>>> ip prefix-list 1 seq 5 permit 192.0.0.0/3 ge 24 le 24
>>>>
>>>> R2#show ip route rip
>>>> R 223.1.1.0/24 [120/1] via 10.1.12.1, 00:00:19, FastEthernet0/0
>>>> R 200.1.1.0/24 [120/1] via 10.1.12.1, 00:00:19, FastEthernet0/0
>>>> R 192.1.1.0/24 [120/1] via 10.1.12.1, 00:00:19, FastEthernet0/0
>>>> R 195.1.1.0/24 [120/1] via 10.1.12.1, 00:00:19, FastEthernet0/0
>>>>
>>>> if I am using a standard ACL
>>>>
>>>>
>>>> Standard ACL
>>>> R2#show run | sec rip
>>>> router rip
>>>> version 2
>>>> network 10.0.0.0
>>>> distribute-list 1 in FastEthernet0/0
>>>> no auto-summary
>>>>
>>>> R2#show run | sec access-list
>>>> access-list 1 permit 192.0.0.0 31.255.255.0
>>>>
>>>> R2#show ip ro rip
>>>> R 223.1.1.0/24 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
>>>> R 200.1.1.0/24 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
>>>> 193.1.1.0/25 is subnetted, 1 subnets
>>>> R 193.1.1.0 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
>>>> R 192.1.1.0/24 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
>>>> R 195.1.1.0/24 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
>>>> 194.1.1.0/26 is subnetted, 1 subnets
>>>> R 194.1.1.0 [120/1] via 10.1.12.1, 00:00:07, FastEthernet0/0
>>>>
>>>>
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Received on Sun Jun 24 2012 - 23:57:27 ART