How to configure Administrative Distance

This topic is to discuss the following lesson:

Hello Rene,
about access-list, I have to read in this way: for prefix 1.1.1.0/24
my local router in which run ospf,rip and Eigrp have to put in routing table that one learned by Rip…is it correct my reasoning?
well we use access-list to permit that prefix is handle only by rip?

Hi Rene,

Thanks for your post…
Really a very helpful ans straight forward explanation clearing all doubts…
Thanks a lot…

You are welcome Farhan!

Can you please clarify for me?
What is the difference between inter-area and intra-area on ospf?

Intra-area means within the area and inter-area means another area.

Thanks

I don’t get this:

James(config-router)#distance 70 0.0.0.0 255.255.255.255 MY_PREFIXES

What is the meaning of 0.0.0.0 255.255.255.255?

Hi Crytsuone,

0.0.0.0 255.255.255.255 refers to all networks. If we wouldn’t specify the access-list, the AD would change for all networks.

Rene

Hi Rene,
Do the RIP admin distance changes only apply locally or will they be passed on to other RIP routers with the new admin distance?

Hi David,

Good question. Administrative distance is always local…it’s never shared between routers.

Rene

Ok, that makes sense, I have GNS3 and that’s what I was seeing. Just to add to that, I presume that is the same for all internal ADs, unless its being redistributed into another routing protocol?

Hi David,

Yes this applies to all ADs, it’s always a local value and never exchanged between router. Even when you do redistribution, AD is never exchanged. The router uses its own list of ADs (that you can change).

Hope that helps!

Rene

thanks for the quick replies. As my studying has progressed Ive noticed there are so many ways to redirect the traffic and it seems there is not just one definitive way of resolving an issue, which it cool because it gives the ‘programmer’ some creativity in achieving a solution.

Hi David,

You are welcome. There are quite some methods to change traffic patterns…changing the metric, AD, policy-based routing, distribute-lists, offset-lists and so on.

Rene

Rene is there a way to change the External AD of EIGRP by specific? not the whole external, but only some specific EX Routes?

i tried the

distance 150 12.0.0.1 0.0.0.0 1

where access list 1 is “permit host 10.1.1.1”

12.0.0.1 is my source ip where i get EIGRP EX routes. the EX AD is still 170. its not changing

Hi John,

I’ve seen this problem before, for some reason it doesn’t work on EIGRP external routes. I just tried it again myself:

router eigrp 1
distance 80 192.168.12.1 0.0.0.0 1

access-list 1 permit 1.1.1.0 0.0.0.255

Where 192.168.12.1 is the address of the network and 1.1.10/24 is the network I’m trying to change. When it’s an EIGRP internal route it works right away, external it doesn’t…

The only other option is using the “eigrp distance” command for all external routes I think.

Rene

Hi John,

I think there isn’t…

Rene

Thanks. It seems there isn’t. Tried googling it and i cant find some answers

Anyway thanks rene