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Easy question on prefix-list

Hi, imagine I need to allow only traffic from the following networks:

10.1.0.0 /16 
10.175.206.0 255.255.255.0
10.175.207.0 255.255.255.0

between (OSPFDepartmentRouterBGP 100)--------------CorporateRouter (BGP 200)

That said, can you please give me a hint if the following prefix-lists correctly represent the networks above. I know how to get this working with route-map and access-lists but I am new to prefix-lists. Thanks!


DepartmentRouter
router bgp 100
neighbor 10.1.47.193 remote-as 200
redistribute ospf 1 route-map RM_ENG
!
ip prefix-list LIST_ENG seq 5 permit 10.0.0.0/8
ip prefix-list LIST_ENG seq 10 permit 10.175.206.0/24
ip prefix-list LIST_ENG seq 15 permit 10.175.207.0/24
!
route-map RM_ENG permit 10
match ip address prefix-list LIST_ENG
set local-preference 200
!
router ospf 1
router-id 10.1.1.15
redistribute bgp 100 metric 10 subnets route-map RM_ENG
redistribute static metric 50 metric-type 1 subnets
(...)

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: Easy question on prefix-list

I think you want to said to accept the routes from these networks? And you have

ip prefix-list LIST_ENG seq 5 permit 10.0.0.0/8

it should be

ip prefix-list LIST_ENG seq 5 permit 10.1.0.0/16

The end result is only the following 3 routes that will be accept to your routing table

10.1.0.0/16

10.175.206.0/24

10.175.207.0/24

If the remote is sending your a route of 10.1.1.0/24, it will be blocked.

Regards,

jerry

1 REPLY
Cisco Employee

Re: Easy question on prefix-list

I think you want to said to accept the routes from these networks? And you have

ip prefix-list LIST_ENG seq 5 permit 10.0.0.0/8

it should be

ip prefix-list LIST_ENG seq 5 permit 10.1.0.0/16

The end result is only the following 3 routes that will be accept to your routing table

10.1.0.0/16

10.175.206.0/24

10.175.207.0/24

If the remote is sending your a route of 10.1.1.0/24, it will be blocked.

Regards,

jerry

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