What command enables OSPF authentication on an interface?

To enable OSPF authentication on an interface, the command used is "ip ospf authentication." This command is essential for configuring OSPF to ensure that the routing updates exchanged between OSPF routers are validated and secure. By implementing authentication, OSPF can prevent malicious or unintended routing information from being accepted, which enhances the overall security of the routing protocol.

When the "ip ospf authentication" command is entered on the relevant interface, it indicates that the router should use a specific authentication type when sending and receiving OSPF messages on that interface. Following this command, you would typically configure a password for the authentication method being used (such as plain text or MD5).

Understanding this command is crucial for network security; it helps safeguard the OSPF routing process against unauthorized access and manipulation.