Question: I'm getting a TNS "no listener" error on my Windows Oracle database when trying to connect:
LSNRCTL> status
Connecting to [DESCRIPTION=[ADDRESS=[PROTOCOL=TCP][HOST=][PORT=1521]]]
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
TNS-00511: No listener
32-bit Windows Error: 61: Unknown error
Connecting to [DESCRIPTION=[ADDRESS=[PROTOCOL=IPC][KEY=EXTPROC0]]]
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
TNS-00511: No listener
32-bit Windows Error: 2: No such file or directory
Answer: The TNS no listener errors indicate that the Windows listener service is not accepting connections or the service is not running. The docs note the cause and action on the TNS No Listener errors, recommending to re-start the listener:
Cause - The connect request could not be completed because no application is listening on the address specified, or the application is unable to service the connect request in a sufficiently timely manner.
Action - Ensure that the supplied destination address matches one of the addresses used by the listener - compare the TNSNAMES.ORA entry with appropriate LISTENER.ORA file [or TNSNAV.ORA if the connection is to go by way of an Interchange.
Start the listener on the remote machine.