OSPF filter-list
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04-19-2025 01:20 AM - edited 04-19-2025 01:23 AM
R1 --------R2----------R3----------R4
area1 NSSA (r3abr) area0
Router 1 is redistributing lo0 1.1.1.1 (N2). On the ABR, I want to filter 1.1.1.1/32 route from going to Area0 using filter list and it is not working.
ABR R3
!
ip prefix-list R4EXTR seq 5 deny 1.1.1./32
ip prefix-list R4EXTR seq 10 permit 0.0.0.0/0 le 32
!
router ospf 1
router-id 33.33.33.33
area 0 filter-list prefix R4EXTR in
!
I also tried area1 filter-list prefix R4EXTR out
* I am not seeing hits on the prrefix
!
sh ip prefix-list R4EXTR seq 5
seq 5 deny 1.1.1.1/32 (hit count: 0, refcount: 1)
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ASR 1000 Series
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04-19-2025 01:33 AM
Try use in ASBR nssa-only' this will make ABR between area0 and areax (nssa area) rejest transfer from lsa7 to lsa5 and hence LO will only appear in areaX
MHM
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04-19-2025 01:35 AM
I get it, the filter-list will only filter LSA-3. In my case, the route is a TYPE 5
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04-19-2025 09:46 AM
Hello
Because R3 is the ABR of the NSSA, you should be able to use a summary to filter
R3
----
router ospf x
summary-address 1.1.1.1 255.255.255.255 no-advertise
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Kind Regards
Paul
