No Route to Host Exception when trying to connect to OpenMQ?

Question

Hi,
I'm trying to connect to an OpenMQ server running on another machine with code like the following:
        com.sun.messaging.ConnectionFactory f = new com.sun.messaging.ConnectionFactory();
        String host = "192.168.181.181";
        int timeOut = 10 * 1000;
        boolean reachable = InetAddress.getByName(host).isReachable(timeOut);
        System.out.println("reachable=" + reachable);
        f.setProperty(ConnectionConfiguration.imqAddressList,             host );
        f.setProperty(ConnectionConfiguration.imqAddressListBehavior, "RANDOM");
        f.setProperty(ConnectionConfiguration.imqConsumerFlowLimit,   "10");
        f.setProperty(ConnectionConfiguration.imqReconnectEnabled,    "true");
        Connection myConnection = f.createConnection();This tells me that the machine is not reachable (via my print) and throws a NoRouteToHostException. My problem is that the machine is reachable. It responds to pings and I can use telnet to see the OpenMQ server is running:
curt@ccox-u1:~$ telnet 192.168.181.181 7676
Trying 192.168.181.181...
Connected to 192.168.181.181.
Escape character is '^]'.
101 DEV_MQ_Cluster 4.2
portmapper tcp PORTMAPPER 7676 [imqvarhome=/var/opt/sun/mq,brokerid=bossnode1,imqhome=/opt/sun/mq,sessionid=8595155628813678592]
cluster_discovery tcp CLUSTER_DISCOVERY 32811
jmxrmi rmi JMX 0 [url=service:jmx:rmi://foo.com/stub/rO0ABXNyAC5qYXZheC5tYW5hZ2VtZW50LnJlbW90ZS5ybWkuUk1JU2VydmVySW1wbF9TdHViAAAAAAAAAAICAAB4cgAaamF2YS5ybWkuc2VydmVyLlJlbW90ZVN0dWLp/tzJi+FlGgIAAHhyABxqYXZhLnJtaS5zZXJ2ZXIuUmVtb3RlT2JqZWN002G0kQxhMx4DAAB4cHc6AAtVbmljYXN0UmVmMgAADzE5Mi4xNjguMTgxLjE4MQAAgCwTQLe4tsgNM+WcbkQAAAEggVyr4oABAHg=]
admin tcp ADMIN 32814
jms tcp NORMAL 32813
cluster tcp CLUSTER 32815
Connection closed by foreign host.Can anyone tell me why this fails or give me some troubleshooting hints?
Thanks,
Curt
PS -- Here's what I'm running:
curt@ccox-u1:~$ java -version
java version "1.6.0_10"
Java(TM) SE Runtime Environment (build 1.6.0_10-b33)
Java HotSpot(TM) Server VM (build 11.0-b15, mixed mode)
curt@ccox-u1:~$ cat /proc/version
Linux version 2.6.27-11-generic (buildd@vernadsky) (gcc version 4.3.2 (Ubuntu 4.3.2-1ubuntu11) ) #1 SMP Wed Apr 1 20:57:48 UTC 2009

Answer 1

There are two problems here. The first is a firewall problem. Although the Open MQ port mapper running on port 7676 wasn't being blocked, the port that mq tcp port was. I was able to solve this by creating an ssh tunnel and specifying a mqtcp connection.
"Table 18–2 Message Broker Addressing Schemes"
http://docs.sun.com/app/docs/doc/820-4916/6ngbm6hp4?a=view#gbnnt
f.setProperty(ConnectionConfiguration.imqAddressList,"mqtcp://" + host + ":32782/jms");This solution is less than ideal, since the mq tcp port can change. In fact, if you reference the original post, you can see it has already changed on me. I could write code to determine what the port is and create my own tunnel, but that doesn't seem worth the effort just yet.
The second problem is the lack of helpful error message. It's the sort of problem where you can't really blame any one party too much. Open MQ and Java are both just reporting the error message that they are given by the operating system. They should do a bit more than that.