As explained in PETALSESBCONT-371, the JMX host can't be configured, nevertheless the way JMX works with RMI makes this information important.
Basically, the JMX server registers itself in the RMI registry.
The RMI registry thus contains the host where the server is located and by default it uses localhost.
This means that a remote connection can get the information from the RMI registry but then fails to connect to the JMX server.
This is a known problem (see http://docs.oracle.com/javase/7/docs/technotes/guides/rmi/faq.html#domain) and there may be cases where the bug wasn't visible...