Configuring OSPF interface authentication

Optional: OSPF supports two methods of authentication for each VLAN or subnet—simple password and MD5. In addition, the value can be disabled, meaning no authentication is performed. Only one method of authentication can be active on a VLAN or subnet at a time, and if one method is configured on an interface, configuring the alternative method on the same interface automatically overwrites the first method used.

In the default configuration, OSPF authentication is disabled. All interfaces in the same network or subnet must have the same authentication method (password or MD5 key chain) and credentials.