3Com Switch 8800 Configuration Guide Chapter 22 IP Routing Policy Configuration
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22.2.2 Configuring ip-prefix
z A prefix-list is identified by an ip-prefix-name. Each IP prefix-list may include
multiple entries each specifying an IP prefix matching range. IP prefix entries are
identified by index-numbers. The order in which IP prefix entries are matched
against depends on the order of their index numbers.
Perform the following configuration in system view.
Table 22-4 Define prefix-list
Operation Command
Define prefix-list
ip ip-prefix ip-prefix-name [ index index-number ] { permit |
deny } network len [ greater-equal greater-equal ]
[ less-equal less-equal ]
Remove prefix-list undo ip ip-prefix ip-prefix-name [ index index-number |
permit | deny ]
During the matching, the router checks list items identified by the index-number in the
ascending order. If only one list item meets the condition, it means that it has passed
the ip-prefix filtering (will not enter the testing of the next list item).
Note that if more than one ip-prefix item are defined, then the match mode of at least
one list item should be the permit mode. The list items of the deny mode can be firstly
defined to rapidly filter the routing information not satisfying the requirement, but if all
the items are in the deny mode, no route will pass the ip-prefix filtering. You can define
an item of permit 0.0.0.0/0 greater-equal 0 less-equal 32 after the multiple list items in
the deny mode so as to let all the other routes pass.
22.2.3 Configuring the AS Path List
The routing information packet of the BGP includes an autonomous system path
domain. The as path-list can be used to match with the autonomous system path
domain of the BGP routing information so as to filter the routing information, which does
not conform to the requirements.
Perform the following configuration in the system view:
Table 22-5 Define the AS path list
Operation Command
Define the AS path list ip as-path-acl acl-number { permit |
deny } as-regular-expression
Delete the specified AS path list undo ip as-path-acl acl-number
By default, no AS path list is defined.