Route & prefix list - duplications

[suthomas1]

Hello All,

For IP Subnet 10.230.126.16 /29 , below routes are seen on a router.

ip route 10.230.126.0 255.255.248.0 Vlan201 10.230.201.254
ip prefix-list sys-to-innw seq 60 permit 10.230.126.0/21

and there are also more specific ones seen as below:

ip route 10.230.126.16 255.255.255.248 Vlan201 10.230.201.254
ip prefix-list sys-to-innw seq 1320 permit 10.230.126.16/29

When i check the routes, it seems the /21 one (first ones) will suffice for traffic related to subnet
10.230.126.16 /29. We are looking to clean-up some unwanted stuff.
But i wanted to have a second opinion here, just to be sure i am not wrong.

sh ip route 10.230.126.18
Routing entry for 10.230.126.16/29
  Known via "static", distance 1, metric 0
  Redistributing via bgp 65190
  Advertised by bgp 65190
  Routing Descriptor Blocks:
  * 10.230.201.254, via Vlan201
      Route metric is 0, traffic share count is 1

And if it is safe to remove the more specific one /29(both route & prefix list), will it cause any impact
to traffic already using the above subnets.

Appreciate all reply. Thanks in advance.

[Masoud Pourshabanian · Accepted solution]

Hello,

Check the output of this command to make sure 10.230.126.0/21 is inside the routing table.

sh ip route 10.230.126.14 ( different subnet)

As it appears these routes are redistributed by BGP. Make sure they are redistributed with the same Policy( same metric or as-path or ......). After that you can remove it. It may interrupt the current session, but does not have a very noticeable impact.

Masoud