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

Fixing ORA-12545: When Your Oracle Binary Goes Missing

Recently, while connecting to one of my test database instances, I ran into a frustrating error:

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

At first glance, this looks like a typical network issue — host unreachable, wrong IP, DNS mismatch, etc. But in my case, the root cause was completely different.

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Digging Into the Error

After searching across a few forums and documents, I landed on the Oracle Support Note KB167814 – Troubleshooting guide for ORA-12545 / TNS-12545.
This document outlines three common problem categories along with causes and solutions.

From those, one scenario matched my situation exactly.

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The Actual Problem

Problem:
You are trying to connect locally on the server without using the listener (using BEQ protocol). Such connections can fail with ORA-12545.

Cause:
The Oracle binary is missing from the $ORACLE_HOME/bin directory.

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Diagnosis

To verify, I ran a quick check:

$ cd $ORACLE_HOME/bin
$ ls -l oracle

The result confirmed the problem — the oracle binary was missing.

And without this binary, the database simply cannot function.

What You Lose Without the Oracle Binary

• You cannot start the database
• You cannot mount or open the DB
• You cannot connect as SYSDBA locally
• You cannot use sqlplus / as sysdba

Why?

Because the oracle binary is the actual database engine. Without it, the entire Oracle stack becomes unusable.

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Resolution Options

At this point, I had three practical solutions:

1. Raise an SR with Oracle Support and involve the DB Install team

2. Reinstall the Oracle Home (only the software, not the database)

3. Copy the oracle binary from another server

I chose the 3rd option, but with extreme caution.

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Copying the Oracle Binary: Not as Simple as It Sounds

The oracle executable is not a simple file that you can copy from any system.
It relies on:

✔ Exact OS version
✔ Exact Kernel version
✔ Exact glibc & system libraries
✔ Exact Oracle patch level (RU/RUR)
✔ Identical ORACLE_HOME structure
✔ Identical linking options used during installation

If any of these differ, the copied binary will fail — or worse, cause unpredictable issues.

Fortunately, in my case, the source server matched my environment exactly.
I copied the binary, set the correct permissions, and—good news—my database started successfully.

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Conclusion

The ORA-12545 error is often mistaken as just a networking issue. But sometimes the cause lies deeper inside the Oracle Home itself.
If you're connecting using BEQ and getting ORA-12545, don't forget to check whether your oracle binary actually exists.

A missing binary is rare, but when it happens, knowing the right direction saves enormous troubleshooting time. 

Thanks & Regards,

Chandan Tanwani