In the spfile of a single instance database, LOCAL_LISTENER is set to LISTENER_1.

Dynamic service registration cannot be used for this database instance

The LREG process registers services dynamically with the LISTENER_1 listener

LISTENER_1 must also be defined in the LISTENER.ORA file to enable dynamic service registration

There are two listeners named LISTENER and LISTENER_1 running simultaneously using port 1521 on the same host as the database instances

The definition for LISTENER_1 requires a CONNECT_DATA section to enable dynamic service registration