Dell PowerConnect B-RX Configuration Manual page 778

25
Configuring OSPF
TABLE 108
IP prefix list
XXX
Not defined
Not defined
Defined (no rules
configured)
Defined (rules
configured)
Defined (rules
configured)
Defined (rules
configured)
Configuring an OSPF area prefix list
To filter prefixes advertised in type 3 link-state advertisements (LSAs) between (OSPF) areas of an
Area Border Router (ABR), use the area prefix-list command in router configuration mode. To
change or cancel the filter, use the no form of this command.
Configuring OSPF ABR type 3 LSA filtering
To filter inter-area routes into a specified area, use the following commands beginning in router
configuration mode.
To configure the router to run an OSPF process, enter commands such as the following.
BigIron RX(config)# router ospf
BigIron RX(config-ospf-router)#
To filter prefixes advertised in type 3 link-state advertisements (LSAs) between (OSPF) areas of an
Area Border Router (ABR), use the area prefix-list command in router configuration mode. To
change or cancel the filter, use the no form of this command.
BigIron RX(config-ospf-router)#area 1 prefix-list area 1 in
To configure the switch to filter inter-area routes out of the specified area, enter a command such
as the following.
BigIron RX(config-ospf-router)# area 10.10.10.1 prefix-list Routesfor20 out
Syntax: [no] area {<area-id> | <area_ip>} prefix-list {prefix-list-name in | out}
The < prefix-list-name > parameter specifies the prefix list name.
The {<area-id> | <area_ip>} parameter specifies the area id in different formats.
706
•
With this feature enabled in the "out" direction, all type 3 LSAs advertised by the ABR,
based on information from this area to all other areas, are filtered by the prefix list. If the
area range command has been configured for this area, Type 3 LSAs that corresponds to
the area range command are treated like any other type 3 LSA.
•
Prefixes that are not permitted by the prefix list are implicitly denied.
•
The following table displays the behavior for prefix list configurations
Behavior for prefix list configurations
OSPF area prefix list
Not defined
Defined
Defined
Defined
Defined
Defined
Defined
Event
None
None
IP prefix list defined
None
IP prefix list deleted
IP prefix list rule added or
modified or deleted
Area prefix list deleted
BigIron RX Series Configuration Guide
Filtering done
No (permit all)
Yes (deny all)
Recalculation
Implicit deny (deny all)
Recalculation and deny all
Recalculation
Recalculation and permit all
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