1-3TaskDefining Filters Defining an IP-prefix ListCreating a Route PolicyDefining if-match ClausesConfiguring a Route PolicyDefining apply ClausesDefining FiltersPrerequisitesBefore configuring this task, you need to decide on:z IP-prefix list namez Matching address rangeDefining an IP-prefix ListDefine an IPv4 prefix listIdentified by name, an IPv4 prefix list can comprise multiple items. Each item specifies a prefix range tomatch and is identified by an index number.An item with a smaller index number is matched first. If one item is matched, the IP prefix list is passed,and the routing information will not go to the next item.Follow these steps to define an IPv4 prefix list:To do… Use the command… RemarksEnter system view system-view —Define an IPv4 prefixlistip ip-prefix ip-prefix-name [ indexindex-number ] { permit | deny } ip-addressmask-length [ greater-equal min-mask-length ][ less-equal max-mask-length ]RequiredNot defined by default.If all the items are set to the deny mode, no routes can pass the IPv4 prefix list. Therefore, you need todefine the permit 0.0.0.0 0 less-equal 32 item following multiple deny items to allow other IPv4 routinginformation to pass.For example, the following configuration filters routes 10.1.0.0/16, 10.2.0.0/16 and 10.3.0.0/16, butallows other routes to pass. system-view[Sysname] ip ip-prefix abc index 10 deny 10.1.0.0 16[Sysname] ip ip-prefix abc index 20 deny 10.2.0.0 16[Sysname] ip ip-prefix abc index 30 deny 10.3.0.0 16[Sysname] ip ip-prefix abc index 40 permit 0.0.0.0 0 less-equal 32
