Can I use the distribute-list in/out command with OSPF to filter routes?

Configuring distribute-list commands that utilize route maps is not achieving desired Link-State Advertisement (LSA) filtering.

Open Shortest Path First Protocol (OSPF) routes cannot be filtered from entering the OSPF database.

The distribute-list in command only filters routes from entering the routing table, and it does not prevent LSA packets from being propagated.

In the route map, the user can match on any attribute of the OSPF route.

The route map could be based on these match options:

	match interface
	match ip address
	match ip next-hop
	match ip route-source
	match metric
	match route-type
	match tag

To define a route map to prevent OSPF routes from being added to the routing table refer to:

OSPF Inbound Filtering Using Route Maps with a Distribute List

The updates or LSA can be blocked with the following command.

This works for ipv6 addresses:

distribute-list prefix-list list-name {in [interface-type interface- number]|out routing-process [as-number]}

For information about the blocking the updates or LSA that are received or sent on an interface refer to:

distribute-list prefix-list (IPv6 OSPF)

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• Cisco
• LANs / WANs
• Configuring distribute-list commands that utilize route maps
• distribute-list in command
• distribute-list prefix-list (IPv6 OSPF)
• distribute-list prefix-list list-name
• interface-type interface- number
• ipv6 addresses
• Link-State Advertisement (LSA) filtering