OSPF help

[Jeza-925]

Hi all,

Can somebody please help me understand what is being advertised from this router over ospf:

!
interface Loopback0
description ConnectionToBranch
ip address 10.16.7.254 255.255.255.255
!
!
router ospf 1
redistribute static subnets route-map STATIC-PERMIT
passive-interface Loopback0
network 10.16.7.254 0.0.0.0 area 0
network 10.255.0.0 0.0.255.255 area 0
distribute-list route-map LISTA in
!
ip route 0.0.0.0 0.0.0.0 10.16.253.1 130
ip route 10.0.253.2 255.255.255.255 10.16.253.1
ip route 10.16.0.0 255.255.0.0 10.16.253.1
ip route 10.16.0.0 255.255.248.0 10.16.252.1
ip route 10.30.254.2 255.255.255.255 10.16.253.1
!
!
ip prefix-list LISTA seq 10 permit 0.0.0.0/0
ip prefix-list LISTA seq 20 permit 10.30.7.254/32
!
ip prefix-list STATIC seq 10 permit 10.16.0.0/21
!
!
route-map STATIC-PERMIT permit 10
match ip address prefix-list STATIC
!
route-map LISTA permit 10
match ip address prefix-list LISTA
!

If I understand this correctly distribute-list is allowing everything to route table with permit 0.0.0.0/0? What is advertised to other router? What is the purpose of STATIC commands?

Thanks in advance.

[balaji.bandi]

If I understand this correctly distribute-list is allowing everything to route table with permit 0.0.0.0/0? What is advertised to other router? What is the purpose of STATIC commands?

we are not sure full topology you working on, based on this information - 

distribute-list route-map LISTA in   - you filtering the routes coming in

redistribute static subnets route-map STATIC-PERMIT  - this matches your  -ip prefix-list STATIC seq 10 permit 10.16.0.0/21

One of a good example explained here :

https://lpmazariegos.com/2016/04/01/ospf-filtering-part-iii/

[Martin L]

not exactly, permit 0.0.0.0/0 without le or ge 32 means only default route.  To permit All prefixes you need permit 0.0.0.0/0 le 32.

So, it looks like distribute-list route-map LISTA in permits default route o.o.o.o/o and 10.30.7.254/32; none others are permitted because of missing permit any (0.0.0.0/0 le 32) at the end of statement.

And, redistribute static  subnets  means redistribute static routes into osfp - you have 5 - but since there is route map attached ospf lets only 10.16.0.0/21 to be redistributed. STATIC seq 10 permit 10.16.0.0/21

Regards, ML
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