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Oracle Troubleshooting

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

Symptom:

When trying to connect to Oracle the following error is generated:

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

Cause:

Oracle suggest that this error indicates that the address specified (in the alias definition) is not valid.

Possible Remedies:

  • Oracle suggest ensuring that the ADDRESS parameters (in the TNSNAMES.ORA file) 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.
  • It could be a network connectivity problem. Try pinging the host. This error has been observed on a laptop when the database was local, TCP/IP protocol used but the network card had been removed.

This page represents one page of many pages of notes I made whilst working with Oracle 7 through to 10i. I now no longer work with Oracle databases, but hope that these notes will continue to be of benefit to others.

About the author: is a dedicated software developer and webmaster. For his day job he develops websites and desktop applications as well as providing IT services. He moonlights as a technical author and consultant.