The filter-policy export command configures a filtering policy to allow IS-IS to filter the imported routes to be advertised.
The undo filter-policy export command cancels the filtering function.
By default, IS-IS does not filter the imported routes to be advertised.
filter-policy { acl-number | acl-name acl-name | ip-prefix ip-prefix-name | route-policy route-policy-name } export [ protocol [ process-id ] ]
undo filter-policy [ acl-number | acl-name acl-name | ip-prefix ip-prefix-name | route-policy route-policy-name ] export [ protocol [ process-id ] ]
| 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. |
protocol |
Specifies the imported routes that need to be filtered when the routes are advertised. If this parameter is not specified, all the imported routes to be advertised are filtered. |
The value can be direct, static, unr, rip, bgp, ospf, or another isis process. |
process-id |
Specifies the process ID if protocol is rip, ospf, or another isis process. |
The value is an integer that ranges from 1 to 65535. |
Usage Scenario
When IS-IS and other routing protocols are running on the network, and a boundary router in the IS-IS routing domain has imported routes of other routing protocols, the boundary router will advertise all the imported routes to its IS-IS neighbors by default. To advertise some of the imported routes to neighbors, use the filter-policy export command.
Precautions
Running the filter-policy export command does not affect the routes on the local device, but only advertises specific imported routes to IS-IS neighbors.
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 external routes of the specified routing domain that are imported by IS-IS are advertised to the specified neighbor.
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 external routes of the specified routing domain that are imported by IS-IS are advertised to the specified neighbor.