Server hangs after disconnecting clients via VPN

Hello,

 

Some time ago I started to use openJMS in a small software project. We
use it just to send simple String messages back and fro.

 

This all kept working fine, until we used our application on a remote
site where we used VPN to connect windows clients to the JMS server.

When a client, disconnects, we see (via netstat) that the connection
keeps the status "ESTABLISHED"... and this for a very long time (longer
than a day!)

This would not be a problem, if the server kept working... But it hangs
!  It accepts new incoming clients, but when a session is created on the
connection, the method blocks for an infinite time.

All clients that were connected at that time keep working, but new
connections are hanging. The problem only disappears when the JMS server
is restarted !

 

For the server, we use a fairly default configuration, only use the
default derby DB. 

The client uses the API jars.

 

To illustrate where the problem occurs, the code extract:

 

javax.jms.ConnectionFactory factory = (ConnectionFactory)
context.lookup("TCPConnectionFactory");
javax.jms.Connection connection = factory.createConnection();

// blocks here forever !
// -----------------------
javax.jms.Session session = connection.createSession(false,
Session.AUTO_ACKNOWLEDGE);
// -----------------------

 

I enabled debug logging on the server side, but it does not report
anything strange as far as I can see.

 

The scenario how I can reproduce this phenomenon is the following:

(using Windows XP and VPN connection)
1) Start a VPN connection to remote network with our openJMS server. Let
it only have a Topic with a TCP connection factory configured.
2) connect a JMS client application (via the VPN connection) and let it
send repeated messages to the topic (send/receive)
3) disconnect hard the VPN connection while client is sending/receiving
4) check on remote site that network connection was still in netstat.
5) the JMS server now hangs, and does allow incoming connections, but
blocks on all other connecting clients when creating a session on that
connection.
6) situation only resolves when restarting JMS server again.

 

 

The problem occurs on Linux, Windows and even on AS/400.

 

Hope anyone can give any suggestions. Regards,

Peter De Leuze


Computer support NV : www.computersupport.be

Empowering your Business Through IT.

 

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