I have box A and it has a consumer on it that listens on a Rabbit MQ server
I have box B that will publish a message to the listener
So as long as all of this in
did you try adding?
RABBITMQ_NODE_IP_ADDRESS=box.a.ip.addy
to the /etc/rabbitmq/rabbitmq.conf file?
Per http://www.rabbitmq.com/configure.html#customise-general-unix-environment
Also per this documentation it states that the default is to bind to all interfaces. Perhaps there is a configuration setting or environment variable already set in your system to restrict the server to localhost overriding anything else you do.
UPDATE: After reading again I realize that the telnet should have returned "Connection Refused" not "No route to host." I would also check to see if you are having a firewall related issue.