06-01-2024 02:09 AM
Hi! Is there a way to filter OSPF routes without the "Area" command?
I could swear I've done it before, but I can't seem to replicate it again.
I am in CML, and my topology is R1--R2--R3.
Link between R1 to R2 is area 0, R2 to R3 area 1.
From what I recall from my previous attempts, I used a distribute-list to filter routes from R1 to R3 by placing it on the ABR, R2. Now, I have tried using a prefix-list in my distribute-list both in and out of R2. In of course removes it from R2's routing table, but I do have a memory of it removing the route from R3 aswell?
Answers appreciated. Thanks!
06-01-2024 02:44 AM
area <X> filter-list prefix <> IN/OUT
this command can use instead of area range
MHM
06-01-2024 02:53 AM
That is using the Area command though.
06-01-2024 02:54 AM
area BUT not area range
MHM
06-01-2024 02:55 AM
That is not what I asked for, but thanks anyways.
06-01-2024 03:02 AM
In of course removes it from R2's routing table, but I do have a memory of it removing the route from R3 aswell?
you can not use distribute-list to remove prefix from DB of OSPF so you have only two option
1- area range
2- area filter-list
that all I have
goodluck
MHM
06-01-2024 03:04 AM
Alright. Thanks for the help, maybe I mixed it up.
06-01-2024 03:14 AM
Managed to make it work again. I added another router:
R1--R2--R3--R4.
I made a prefix-list on R3 denying the link between R1 to R2 from being advertised to R4. On R3: "Distribute-list prefix prefix in", R3 being ABR between area 0 and area 1, this prevented the route from being learned on R4.
06-01-2024 03:22 AM
One prefix or ALL prefix will effect by this list?
add LO in R1 and see if R4 see it or not
I think you make all R1/R2 hidden from R4 not only one prefix
MHM
06-01-2024 03:28 AM
The link between R1-R2 is removed, but R1's loopback is still visible on R4.
"Ip prefix-list NOR1 deny 12.12.12.0/29"
"Ip prefix-list NOR1 permit 0.0.0.0/0 le 32"
"Distribute-list prefix NOR1 in" on R3
The route to 10.10.10.1 (R1's lo0) is still visible on R4.
06-01-2024 03:33 AM
In R4 and R3 can I see show ip route
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