3Com 10014299 manual Define an IP Prefix List, Ip ip-prefix prefix-list-name

Configure IP Routing Policy 485

type is the type of ospf external route corresponding to the imported route when ospf is importing other protocol routes. type 1 refers to external route type 1 and type 2 refers to external route type 2.

The metric value of the imported route can be set as the following:

1Specify the metric value with the apply cost command.

2Filter the route with routing policy and set attributes for the route matching the conditions.

3If neither of the above is specified, the imported route uses the default metric value. The default metric can be specified with the default-medcommand.

When both routing policy and med value are specified, the routing information matching the routing policy will use the metric specified by the apply command of a routing policy.

Defining an IP Prefix List An IP prefix list is identified with the list name and consists of several parts, with the sequence-numberspecifying the matching order of these parts. In each part, you can specify an individual matching range in the form of network prefix.

It should be noted that:

■In the process of matching, different parts of different sequence-numbersuse Boolean “OR” operations and the routing information matches different parts in turn. Matched with a specific part of the IP prefix list is considered as successfully filter through this IP prefix list

Perform the following configurations in system view.

Table 564 Define an IP Prefix List

Operation	Command
Define an IP prefix list	ip ip-prefixprefix-list-name [
	index index-number] { permit deny
	} network/len [ greater-equal
	ge-value ] [ less-equalle-value ]
Cancel an IP prefix list	undo ip ip-prefix prefix-list-name[
	index seq-number] [ permit deny ]

By default, no IP prefix list is defined.

Configuring Route Filter In some cases, only the routing information that meets the condition should be distributed or imported, to prevent the neighboring routers from receiving private information of other routes. A prefix-list or access list in the route strategy is used to filter the routing information.

Perform the following configurations in RIP view, OSPF view, or BGP view.

1Configure filtering route information received

Define a strategic rule and quote an ACL or prefix-list to filter the routing information that does not meet the requirements when receiving routes. Specify an IP prefix list through gateway keywords, filtering the address of the information router to receive only the updating messages from specific neighboring routers.