The filter-policy import command configures IS-IS to filter the received routes to be added to the IP routing table.
The undo filter-policy import command disables the filtering function.
By default, the filtering function is disabled.
filter-policy { acl-number | ip-prefix ip-prefix-name | route-policy route-policy-name } import
filter-policy { acl6-number | ipv6-prefix ipv6-prefix-name | route-policy route-policy-name } import
undo filter-policy import
undo filter-policy { acl-number | ip-prefix ip-prefix-name | route-policy route-policy-name } import
undo filter-policy { acl6-number | ipv6-prefix ipv6-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 ranging from 2000 to 2999. |
| ip-prefix ip-prefix-name | Specifies the name of the 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. |
| acl6-number | Specifies the number of a basic ACL6. | The value is an integer ranging from 2000 to 2999. |
| ipv6-prefix ipv6-prefix-name | Indicates the name of an IPv6 address 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 the routing policy that is used to filter the routes based on tag and other specific parameters for the protocol. | 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.
Prerequisites
IS-IS processes have been enabled.
Configuration Impact
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.
Precautions
The filter-policy { acl-number | acl-name acl-name | ip-prefix ip-prefix-name | route-policy route-policy-name } import command is used to configure the route filtering function in an IPv4 base topology or an IPv4 topology instance.
The filter-policy { acl6-number | acl6-name acl6-name | ipv6-prefix ipv6-prefix-name | route-policy route-policy-name } import command is used to configure the route filtering function in an IPv6 topology instance.
The ipv6 filter-policy { acl6-number | acl6-name acl6-name | ipv6-prefix ipv6-prefix-name | route-policy route-policy-name } import command is used to configure the route filtering function in an IPv6 base topology.
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.