Shulou(Shulou.com)06/01 Report--

OSPF filtering

1. Filter-policy import (configured in the ospf process)

This command can only suppress the generation of routing entries, so no matter what routes are generated, they can be filtered. But you can't stop LSA from flooding.

[R3-ospf-1] undo filter-policy ip-prefix 1 import

2. Filter-policy export (configured in the ospf process)

This command is used to filter ASE/NSSA on ASBR. In fact, it suppresses the generation of LSA. Once LSA is generated, this command is useless. In addition, this command can only be configured on ASBR. It is not useful to configure other routes because LSA has been generated.

[R1-ospf-1] undo filter-policy ip-prefix 1 export

3. Asbr-summary not-advertise (configured in the ospf process)

This command is used to filter the self-generated ASE/NSSA on ASBR. In fact, it also suppresses LSA generation, and there is no related LSA in the local LSDB.

[R1-ospf-1] undo asbr-summary 11.11.11.11 255.255.255.255

4. Filter import/export (configured in the area)

This command is used on ABR to filter three types of LSA, whether they are self-generated or received from other routers. Invalid for five types of LSA.

[R3-ospf-1-area-0.0.0.0] undo filter ip-prefix 1 export

[R3-ospf-1-area-0.0.0.200] undo filter ip-prefix 2 import

5. Abr-summary not-advertise (configured in the area)

This command is used to filter three types of LSA on ABR, but only three types of LSA generated by yourself can be filtered, not three types received from other devices. (the reason is: this command is an aggregation command. Currently, the aggregation command of VRP and IOS only aggregates the routes in the local area, but not the inter-area routes, so the abr-summary not-advertise command actually only filters the intra-area routes in the local area.)

6. Ospf filter-lsa-out (configured on the interface)

You can filter any type of LSA, and you need to clean up the process after configuration.

[R4-GigabitEthernet0/0/1] undo ospf filter-lsa-out

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