Java – JPS cannot connect to remote jstatd

I'm using jstatd to query a remote JVM using JPS so that I can eventually monitor it using visual VM

I use jstatd to run the following security policies:

grant codebase "file:${java.home}/../lib/tools.jar" {

    permission java.security.AllPermission;
};

Jstatd is running on a 64 bit Linux chassis with 1.6 0_ 10 version of hotspot VM The jstatd command is:

jstatd -J-Djava.security.policy=jstatd.tools.policy -J-Djava.rmi.server.logCalls=true

I tried to run JPS from a Windows 7 machine Due to the limitation of firewall, I tunnel RMI data to my windows machine through SSH tunnel, so the JPS command line is:

.\jps.exe -m -l rmi://localhost

When I run JPS, I see the connection attempts in the jstatd log, as follows:

Feb 1,2011 11:50:34 AM sun.rmi.server.UnicastServerRef logCall
FINER: RMI TCP Connection(3)-127.0.0.1: [127.0.0.1: sun.rmi.registry.RegistryImpl[0:0:0,0]: java.rmi.Remote lookup(ja   va.lang.String)]

But on the JPS side, I get the following error:

Error communicating with remote host: Connection refused to host: 192.168.1.137; nested exception is:
    java.net.ConnectException: Connection refused: connect

According to the connection attempts listed in the jstatd log, I think JPS actually reached the host, but it was blocked for some reason Are there any security policies or other settings I set that can be changed so that I can get JPS statistics from remote jstatd?

Solution

My guess is that you only forward RMI registry port (1099), but you need to open another port

Check remote port

# netstat -nap | grep jstatd

tcp        0      0 :::1099     :::*       LISTEN      453/jstatd          
tcp        0      0 :::58204    :::*       LISTEN      453/jstatd

In this case, you need to forward ports 58204 and 1099