I am trying to set up ehcache replication as documented here: http://ehcache.sourceforge.net/EhcacheUserGuide.html#id.s22.2
This is on a Windows machine but will ultimately run on Solaris in production.

The instructions say to set up a provider as follows:

 <cacheManagerPeerProviderFactory
     class="net.sf.ehcache.distribution.RMICacheManagerPeerProviderFactory"
     properties="peerDiscovery=automatic, multicastGroupAddress=230.0.0.1,
     multicastGroupPort=4446, timeToLive=32"/>

And a listener like this:

<cacheManagerPeerListenerFactory
    class="net.sf.ehcache.distribution.RMICacheManagerPeerListenerFactory"
    properties="hostName=localhost, port=40001,
    socketTimeoutMillis=2000"/>

My questions are:
Are the multicast IP address and port arbitrary (I know the address has to live within a specific range but do they have to be specific numbers)?
Do they need to be set up in some way by our system administrator (I am on an office network)?

I want to test it locally so am running two separate tomcat instances with the above config. What do I need to change in each one? I know both the listeners can't listen on the same port - but what about the provider?
Also, are the listener ports arbitrary too?

I've tried setting it up as above but in my testing the caches don't appear to be replicated - the value added in one tomcat's cache is not present in the other cache.
Is there anything I can do to debug this situation (other than packet sniffing)?

Thanks in advance for any help, been tearing my hair out over this one!