I don't understant why -b 0.0.0.0 isn't working. If you start the server with this option check whether you can access via browser from a different machine with 192.168.6.100:8080 it should work.
If you start with the -b option you do not need to hide JBoss, the 8080 port is only for applications deployed on JBoss and your app is using RMI only right?
So you can't access the application via 8080.
The management http interface is available on port 9990 but as you don't change the interface (-bmanagement x.x.x.x) it should run on localhost and not accessible for others.
If you don't want the port 8080 opened you might remove all services listen on that port from your standalone.xml, but this is only possible if you do not need the http access.
Wolf