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Don Burleson Blog 







TNS-12545:  Connect Failed Because Target Host or Object Does Not Exist tips

Expert Oracle Database Tips by Donald BurlesonDecember 6, 2015

Question: When I try to connect to Oracle in SQL*Plus I get the following error message:

TNS-12545: Connect failed because target host or object does not exist

What is the cause of the TNS-12545 error?

Answer:  The oerr utility shows this for the TNS-12545 error:  See here, on how to use oerr to look up error messages.

TNS-12545:  Connect failed because target host or object does not exist

Cause:  The address specified is not valid, or the program being connected to does not exist.

Action:  Ensure the ADDRESS parameters have been entered correctly; the most likely incorrect parameter is the node name. Ensure that the executable for the server exists (perhaps "oracle" is missing.)

If the protocol is TCP/IP, edit the TNSNAMES.ORA file to change the host name to a numeric IP address and try again.

This TNS-12545 error is almost always an issue in your tnsnames.ora file, specifically your ADDRESS parameter, often a bad host name (node name).

As a test for the DNS, temporarily replace the host name with the IP address, see here for details.

Please go through these steps to diagnose the connectivity issue.

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