3Com 7700 Configuration Manual page 112

104 C 5: R P
HAPTER OUTING
O
ROTOCOL PERATION
Perform the following configurations in system view.
Table 54 Define Prefix-list
Operation
Define a prefix list
Remove a prefix list
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 (and does not enter the testing of the next list item).
Note that if more than one IP prefix item is 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 to let all the other
routes pass.
Configuring Filtering for the Received Routes
Perform the following configuration in routing protocol view.
Define a policy that filters the routing information that does not satisfy the
conditions and receives routes with the help of an ACL or address prefix-list. The
filter-policy gateway command specifies that only the update packets from a
specific neighboring router will be received.
Table 55 Configure Filtering of Received Routes
Operation
Configure to filter the received
routing information distributed by
the specified address
Cancel the filtering of the received
routing information distributed by
the specified address
Configure to filter the received
global routing information
Cancel the filtering of the received
global routing information
Configuring Filtering for the Distributed Routes
Define a policy concerning route distribution that filters the routing information
that does not satisfy the conditions and distributes routes with the help of an ACL
or address ip-prefix.
Command
ip ip-prefix ip-prefix-name [ index index-number ] { permit |
deny } network len [ greater-equal greater-equal ] [
less-equal less-equal ]
undo ip ip-prefix ip-prefix-name [ index index-number |
permit | deny ]
Command
filter-policy gateway ip-prefix-name import
undo filter-policy gateway ip-prefix-name import
filter-policy { acl-number | ip-prefix ip-prefix-name } [
gateway ] import
undo filter-policy { acl-number | ip-prefix
ip-prefix-name } [ gateway ] import