My Oracle Support Banner

Troubleshooting ORA-3135 Connection Lost Contact (Doc ID 787354.1)

Last updated on FEBRUARY 14, 2025

Applies to:

Oracle Net Services - Version 10.2.0.1 and later
Gen 2 Exadata Cloud at Customer - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Database - Enterprise Edition - Version 11.2.0.3 to 12.2.0.1 [Release 11.2 to 12.2]
Oracle Database - Standard Edition - Version 19.5.0.0.0 to 19.5.0.0.0 [Release 19]
Information in this document applies to any platform.

Purpose

Explains why a 3135 error is returned and helps to diagnose the underlying problem.

Troubleshooting Steps

To view full details, sign in with your My Oracle Support account.

Don't have a My Oracle Support account? Click to get started!


In this Document
Purpose
Troubleshooting Steps
 (1) Transparent Application Failover (TAF)
 (2) Idle Connection Timeout
 (3) Firewall Manipulating  Sqlnet Data.
 (4) Data Required for Further Analysis
References

My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.