Which command is used to configure an OSPF password on an interface?

The command used to configure an OSPF password on an interface is "ip ospf authentication-key password". This command specifies the authentication method that OSPF will use to secure OSPF communications on that interface.

When this command is entered, it applies a password for the OSPF protocol, ensuring that OSPF packets sent over this interface are only accepted from routers that configure the same authentication key. This is essential for protecting OSPF routing updates from being accepted from unauthorized devices, enhancing the network's security.

In the context of OSPF, proper authentication is crucial, so using the correct command ensures that OSPF communications maintain integrity and confidentiality. Other commands do not correctly specify the method to set authentication for OSPF on an interface, which makes them ineffective for this purpose.