The filter-policy import command configures a filtering policy to allow IS-IS to filter the received routes to be added to the IP routing table.
The undo filter-policy import command cancels the filtering function.
By default, IS-IS does not filter the received routes to be added to the IP routing table.
filter-policy { acl-number | acl-name acl-name | ip-prefix ip-prefix-name | route-policy route-policy-name } import
undo filter-policy [ acl-number | acl-name acl-name | ip-prefix ip-prefix-name | route-policy route-policy-name ] import
| Parameter | Description | Value |
|---|---|---|
| acl-number | Specifies the number of a basic ACL. | The value is an integer that ranges from 2000 to 2999. |
| acl-name acl-name | Specifies the name of a named ACL. | The value is a string of 1 to 64 case-sensitive characters without spaces. The value must start with a letter. |
| ip-prefix ip-prefix-name | Specifies the name of an IP prefix list. | The name is a string of 1 to 169 case-sensitive characters, with spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string. |
| route-policy route-policy-name | Specifies the name of a route-policy to filter routes based on tag and other protocol parameters. | The name is a string of 1 to 40 case-sensitive characters, with spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string. |
Usage Scenario
IS-IS routing entries need to be added to an IP routing table to guide IP packet forwarding. If an IS-IS routing table has routes destined for a specific network segment, but these routes are not expected to be added to an IP routing table, run the filter-policy import command with specified parameters to allow only the needed IS-IS routes to be added to the IP routing table.
Precautions
Running the filter-policy import command on a router does not affect LSP flooding and LSDB synchronization on the router, but affects the local IP routing table.
For an ACL, when the rule command is used to configure a filtering rule, the filtering rule is effective only with the source address range that is specified by the source parameter and with the time period that is specified by the time-range parameter.
Creating an ACL before it is referenced is recommended. If a nonexistent ACL is referenced using the command, all routes received by IS-IS are delivered to the IP routing table.
Creating an IP prefix list or route-policy before it is referenced is recommended. By default, nonexistent IP prefix lists or route-policies cannot be referenced using the command. If the route-policy nonexistent-config-check disable command is run in the system view and a nonexistent IP prefix list or route-policy is referenced using the current command, all routes received by IS-IS are delivered to the IP routing table.