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Remote or SQL*Net Connections Fail With TNS-12537 Error (Doc ID 333158.1)

Last updated on JANUARY 13, 2020

Applies to:

Oracle Net Services - Version to [Release 8.1.7 to 12.2]
Information in this document applies to any platform.
This problem can occur on any platform.
Some or all remote client connections to the database.


Tnsping Net Service Name fails with TNS-12537: TNS:connection closed
SQL*Plus connections via the listener may thrown an error TNS-12537.

Connection to the Database locally using the bequeath protocol or a TNS connect string will likely be successful.

The problem documented here would be occurring consistently, not intermittently, for remote client connections. 

A level 16 listener trace may reveal the following:


This is likely a new installation and possibly a new Applications installation.


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