java.net.SocketException: No buffer space available (maximum connections reached?): JVM_Bind

Question

Tomcat is running a webapp under Windows. After a few days (under very low load), the exception mentioned in the title starts to appear in the logs, no new connections can be established from that point on, the only fix is then to reboot the server.

Environment:

• Latest Tomcat 6
• Windows Server 2008 R2
• JDK 6 update 30
• SQL Server 2008
• Kerberos authentication

Evidence collected so far:

• netstat shows no excessive amount of connections
• ProcessExplorer shows no excessive amount of open file handles
• system main memory usage is average
• JVM heap usage is average
• restarting Tomcat does not solve the problem

Open questions:

• if we were leaking connections, shouldn't they show up in netstat?
• shouldn't a restart of the appserver resolve the problem, because the OS should free all process resources?
• is there a way to trace the problem to its origin? E.g. installing monitoring software, maybe something similar to lsof etc.?

I'm out of ideas, any hints appreciated!

Answer 1

The reason we got this error is a bug in Windows Server 2008 R2 / Windows 7. The kernel leaks loopback sockets due to a race condition on machines with more than one core, this patch fixes the issue: http://support.microsoft.com/kb/2577795

Answer 2

I was running Alfresco Community 4.0d on Windows 7 64 bit and had the same symptoms and errors.

The problem was fixed with Microsoft's patch: "Kernel sockets leak on a multiprocessor computer that is running Windows Server 2008 R2 or Windows 7" (http://support.microsoft.com/kb/2577795) (ie. Buddy Casino's answer (see below)).

Another observation I'd like to add is that Windows connections (Internet Explorer, Remote Desktop etc) would work again about 5-10 mins after the Alfresco services were shutdown.

Alfresco is an excellent product and I was afraid I would have to scrap it. Fortunately stackoverflow came to the rescue !

Thanks again to Buddy Casino's answer.

Boo to the person who down-voted the Question.