Using two different versions of JBoss on the same network:

1. JBoss AS 3.2.5 in 'all' configuration. Here's the cluster config relative lines:

/cluster-service.xml: <UDP mcast_addr="228.1.2.4" mcast_port="45566"
./jbossweb-tomcat50.sar/sso-channel.xml: ucast_recv_buf_size="800000" mcast_addr="228.8.8.8" loopback="false"
./jbossweb-tomcat50.sar/sso-channel.xml: ucast_recv_buf_size="800000" mcast_addr="228.8.8.8" loopback="false"
./jmx-console.war/WEB-INF/web.xml: <param-value>UDP(ip_mcast=true;ip_ttl=16;loopback=false;mcast_addr=228.1.2.3;mcast_port=45566):

2. A JBoss AS 4.0.3 Final all configuration. Relative cluster config lines (side note: Are these things going to grow ad nauseam?)

[forge@takeshi deploy]$ find . -name '*\.xml' | xargs grep mcast_addr
./cluster-service.xml: <UDP mcast_addr="${jboss.partition.udpGroup:228.1.2.81}" mcast_port="45566"
./jmx-console.war/WEB-INF/web.xml: <param-value>UDP(ip_mcast=true;ip_ttl=16;loopback=false;mcast_addr=${jboss.partition.udpGroup:228.1.2.81};mcast_port=45566):
./tc5-cluster-service.xml: <UDP mcast_addr="${jboss.partition.udpGroup:230.1.2.82}" mcast_port="45577"
./ejb3-entity-cache-service.xml: <UDP mcast_addr="${jboss.partition.udpGroup:228.1.2.81}" mcast_port="43333" ip_ttl="2" ip_mcast="true"
./ejb3-clustered-sfsbcache-service.xml: <UDP mcast_addr="${jboss.partition.udpGroup:228.1.2.88}" mcast_port="45551" ip_ttl="64" ip_mcast="true"
./jboss-portal.sar/conf/cache/replicated.xml: mcast_addr="228.1.2.82" mcast_port="48866"

(Yes, I know that the jboss portal 2.0 'replicated.xml' isn't using the '-u' option. I've reported this bug in JIRA as well under their project.)

I've changed the udp group IP using the '-u' option in jboss as 4.0.3 Final and changed the defaults in each file as you can see above. But I still get the following lines in my 4.0.3 server log:

09:09:28,914 WARN [UDP] packet from /67.19.124.42:32835 has different version (0224) from ours (0227). This may cause problems
09:09:28,914 WARN [UDP] discarded message from different group (DamonPartition). Sender was takeshi:32835 (additional data: 17 bytes)