Chapter 2. OSPF Area Commands
area area-id authentication
This command requires the following additional commands:
For a physical interface: ip ospf authentication-key password (see Section 19-2)
For a virtual link if authentication is used in area 0: area transit-area virtual-link router-id authentication-key password (see Section 2-17)
area-id—. OSPF area ID. This value can be entered as a decimal number in the range of 0 to 4,294,967,295 or in IP address format in the range 0.0.0.0 to 255.255.255.255. This command will enable simple password authentication in the indicated OSPF area. By default, authentication is not enabled.
transit-area—. The OSPF area across which the virtual link is configured.
password—. Clear-text password ...