Re: OSPF LSA Type-3 filtering | Single ABR

Share your OSPF configuration. What area is 1.1.1.1/32 advertised into?

On Sun, Oct 27, 2013 at 3:28 PM, 1000baseT_at_gmail.com <1000baset_at_gmail.com>wrote:

> I was wondering if someone can help shed some light on this situation.
>
> I was practicing various filtering capabilities OSPF with I am came across
> something that doesn't really make sense to me. It involves filtering
> between areas on the SAME abr.
>
>
> Area 0
> |
> <*R1*> -- area 13 -- <*R3*> -- area 32-- <*R2*>
> Prefix =
> 1.1.1.1/32
>
> This came about when I exploring the direction option (In /. out) with the
> filter-list command. This following is what I suspect should have worked,
> but it doesn't seem to when both the ABR is the one generating the Type-3
> and is also the ABR doing the filtering...
>
> Can someone explain why this may be the case...order of operations issue
> maybe? i.e. The ABR sends its locally generated Type-3 LSA locally
> before filtering them?
>
>
> ip prefix-list R1_FILTER den 1.1.1.1/32
> ip prefix-list R1_FILTER per 0.0.0.0/0 le 32
> !
> router ospf 1
> *area 0* filter-list prefix R1_FILTER *out*
>
>
> However all three of the following combinations work as expected:
> router ospf 1
> area 13 filter-list prefix R1_FILTER out
> -or-
> area 32 filter-list prefix R1_FILTER in
> -or-
> area 0 filter-list prefix R1_FILTER in
>
> thanks
>
>
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