ip ospf database-filter

Configures filters for different types of outgoing Link State Advertisements (LSAs).

Syntax

ip ospf database-filter { all-external | all-summary-external { allow-default-and-type-4 | allow-default-out | out } }

ip ospf database-filter all-out

no ip ospf database-filter all-external

no ip ospf database-filter all-out

no ip ospf database-filter all-summary-external

Command Default

All filters are disabled.

Parameters

all-external: Blocks all external LSAs.
all-summary-external: Blocks all summary (Type 3) and external (type 5) LSAs.
allow-default-and-type-4: Allows default-route LSAs and Type 4 LSAs, but block all other LSAs.
allow-default-out: Allows default-route LSAs, but block all other LSAs.
out: Filters outgoing LSAs.
all-out: Blocks all LSAs.

Modes

Interface subtype configuration mode

Usage Guidelines

By default, the device floods all outbound LSAs on all the OSPF interfaces within an area. You can configure a filter to block outbound LSAs on an OSPF interface. This feature is particularly useful when you want to block LSAs from some, but not all, of the interfaces attached to the area. When enabled, this command blocks the specified outgoing LSAs on the interface. Some cases where you might want to enable filters are:

To control the information being advertised to the network.
To use a passive router for debugging only.

The no form of the command disables configurations.

Note

You cannot block LSAs on virtual links.

Examples

The following example applies a filter to block flooding of all LSAs on a specific OSPF Ethernet interface.

device# configure terminal
device(config)# interface ethernet 1/1
device(conf-if-eth-1/1)# ip ospf database-filter all-out