Oracle Error TNS-12170: TNS:Connect timeout occurred

Oracle Error Message

TNS-12170: TNS:Connect timeout occurred

Reason for the Error

The failure to establish a connection or finish communication with a client within the given time period caused the server to shut down.

This could be the consequence of system or network delays, or it could be a sign that a malicious client is attempting to launch a Denial of Service assault on the server.


Change one or more of the parameters SQLNET.INBOUND CONNECT TIMEOUT, SQLNET.SEND TIMEOUT, and SQLNET.RECV TIMEOUT in sqlnet.ora to bigger values if the problem was caused by a slow network or system.

Use the address in sqlnet.log to locate the source and limit access if a malicious client is suspected.

Recall that logged addresses could not be trustworthy since they might be faked (for example, in TCP/IP).