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OSPF Configuration 251
Configuring OSPF Route Filtering
Perform the following configuration in OSPF View.
Configuring OSPF to Filter the Received Routes
Configuring OSPF to filter the distributed routes
By default, OSPF will not filter the imported and distributed routing information.
■ The filter-policy import command only filters the OSPF routes of this process
received from the neighbors, and routes that cannot pass the filter will not be
added to the routing table. This command only takes effect on ABR.
■ The filter-policy export command only takes effect to the routes imported
by the
import-route command. If you configure the Switch with only the
filter-policy export command, but without configuring the import-route
command to import other external routes (including OSPF routes of different
process), then the
filter-policy export command does not take effect.
Configuring the Filling of the MTU Field When an Interface Transmits DD
Packets
OSPF-running routers use the DD (Database Description) packets to describe their
own LSDBs when synchronizing the databases.
You can manually specify an interface to fill in the MTU field in a DD packet when it
transmits the packet. The MTU should be set to the real MTU on the interface.
Perform the following configuration in Interface View:
By default, the interface does not fill in the MTU field when transmitting DD packets,
and the MTU in the DD packets is 0.
Table 245 Enabling OSPF to filter the received routes
Operation Command
Disable to filter the received global
routing information
filter-policy { acl_number | ip-prefix
ip_prefix_name | gateway ip_prefix_name }
import
Cancel to filter the received global
routing information
undo filter-policy { acl_number | ip-prefix
ip_prefix_name | gateway ip_prefix_name }
import
Table 246 Enabling OSPF to filter the distributed routes
Operation Command
Enable OSPF to filter the distributed
routes
filter-policy { acl_number | ip-prefix
ip_prefix_name } export [ routing_ process
]
Disable OSPF to filter the distributed
routes
undo filter-policy { acl_number | ip-prefix
ip_prefix_name } export [ routing_process ]
Table 247 Configuring the Filling of the MTU Field when an Interface Transmits DD Packets
Operation Command
Enable an interface to fill in the MTU field when
transmitting DD packets
ospf mtu-enable
Disable the interface to fill MTU when transmitting DD
packets
undo ospf mtu-enable