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Don Burleson Blog 







TNS-03505: Failed to resolve name tips

Oracle Database Tips by Donald BurlesonJuly 23,  2015

Question:  I'm trying to connect to my database and I an getting this TNS-03505 error:

TNS-03505: Failed to resolve name

What is the difference between "TNS-03505: Failed to resolve name" and "ORA-12154: TNS:could not resolve the connect identifier specified"?

Answer:  Obviously, both TNS-03505 and ORA-12154 are TNS errors; however, they can each have a variety of possible causes and resolutions.

The TNS-03505 error indicates that the service name is missing :

TNS-03505: Failed to resolve name

Cause: The service name you provided could not be found in TNSNAMES.ORA, an Oracle Names server, or a native naming service.

Action: Verify that you entered the service name correctly. You may need to ensure that the name was entered correctly into the network configuration.

Appearing on its own, this essentially means the client has not even gotten to the point of attempting to make contact with a server.  The TNS-03505 is telling you that it simply cannot find any record of the database you are trying to establish a connection with.

Some things to check include the following:

  •  Verify that you have spelled the database name correctly, and that the database has an appropriate entry in the tnsnames.ora, including assurance that the path to the database is correct as sometimes the connection will work when run on a single box but not with connection to a client machine.
  • Verify that there are not multiple tsnnames.ora files as it may be attempting a connection to the wrong database.
  • If connecting to a client machine, make sure there are no firewall issues blocking the connection.

The ORA-12154 error generally indicates you got a little further in the process such that Oracle itself is telling you that it is looking but cannot find the database indicated. Click here for tips on resolving the ORA-12154.




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