Cisco Cisco IOS Software Release 12.2(25)SEC

To enable Open Shortest Path First version 2 (OSPFv2) on an interface, use the ip ospf area command 
in interface configuration mode. To disable OSPFv2 on the interface, use the no form of this command.

ip ospf process-id area area-id [secondaries none] 

no ip ospf process-id area [secondaries none] 

If the secondaries none keywords are entered in the no form of this command, the secondary IP 
addresses will be advertised. If the secondaries none keywords are not present, OSPFv2 will be 
disabled.

Interface configuration

OSPF is enabled on an interface when the network address for the interface matches the range of 
addresses that is specified by the network area command that is entered in router configuration mode. 
You can enable OSPFv2 explicitly on an interface with the ip ospf area command that is entered in 
interface configuration mode. This capability simplifies the configuration of unnumbered interfaces with 
different areas.

The ip ospf area command that is entered in interface configuration mode will supersede the effects of 
the network area command. Therefore, an interface that is configured with the ip ospf area command 
in interface configuration mode will not be affected by the network area command.

If you later disable the ip ospf area command, the interface will still run OSPFv2 as long as its network 
address matches the range of addresses that is specified by the network area command.

A decimal value in the range from 1 to 65535 that identifies the process ID.

A decimal value in the range from 0 to 4294967295, or an IP address.

secondaries none

(Optional) Prevents secondary IP addresses on the interface from being 
advertised.

12.0(29)S

This command was introduced.

12.3(11)T

This command was integrated into Cisco IOS Release 12.3(11)T.

12.2(1)SB

This command was integrated into Cisco IOS Release 12.2(1)SB.

12.2(33)SRB

This command was integrated into Cisco IOS Release 12.2(33)SRB.