Listener Hangs - TNS-01181: Internal registration connection limit reached (Doc ID 549649.1)

Last updated on OCTOBER 27, 2016

Applies to:

Oracle Net Services - Version 9.2.0.1 to 11.2.0.4 [Release 9.2 to 11.2]
Information in this document applies to any platform.
This problem can occur on any platform.

Symptoms

Suddenly the listener starts hanging and any connection attempt via the listener also hangs. The listener needs to be restarted for normal operations but again the listener starts hanging after some time.  A connection attempt from the rogue client or application giving the listener invalid connect data as shown in  the excerpt taken from the listener log OR the listener thinks that the client application is sending bad connect data.

Listener Log:
-----------
....
....

09-JAN-2008 06:23:25 * (CONNECT_DATA=(SID=PSP0)(CID=(PROGRAM=)(HOST=__jdbc__)(USER=))) * service_register_NSGR * 1181
TNS-01181: Internal registration connection limit reached
09-JAN-2008 06:23:25 * (CONNECT_DATA=(SID=PSP0)(CID=(PROGRAM=)(HOST=__jdbc__)(USER=))) * service_register_NSGR * 1181
TNS-01181: Internal registration connection limit reached
....
....

The listener trace file shows the following just before it hangs:

Listener Trace: 
-------------- 
..... 
..... 
nsevwait: waiting for transport event (1 thru 1570)...  <===1570 connections "waiting"
.... 

 

 

 

Adding the following parameter in the listener.ora and setting it to a high value might delay the inevitable listener hang but cannot prevent the listener from hanging.

For Example:
------------
In Listener.ora :

MAX_REG_CONNECTIONS_<listener>=1000

Cause

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