How to configure mod_cluster when there is a NAT between httpd and JBoss?

Issue

I want to bind an EAP instance to a FQDN in order to work around NAT issues with mod_cluster.

I add -b external.example.com as an argument to my start-up script and I see the following error in the logs:

22:17:21,704 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-1) MSC000001: Failed to start service jboss.network.public: org.jboss.msc.service.StartException in service jboss.network.public: JBAS015810: failed to resolve interface public
        at org.jboss.as.server.services.net.NetworkInterfaceService.start(NetworkInterfaceService.java:103) [jboss-as-server.jar:7.5.5.Final-redhat-3]
        at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1980) [jboss-msc.jar:1.1.5.Final-redhat-1]
        at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1913) [jboss-msc.jar:1.1.5.Final-redhat-1]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_85]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_85]
        at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_85]