"bela(a)jboss.com" wrote : Note that multicast loopback is not changed by JGroups - by default it is *enabled* in the OS, so setting IP_MULTICAST_LOOP is superfluous. Yes, I see that now. Do you have a test to check it is working so a RHEL bugzilla can be filed? "bela(a)jboss.com" wrote : I don't understand the other argument: do you want to the OS to pick the NIC, or do you want to set it youself ? If you want to ignore the interface defined by JBoss through -b, then set system property jgroups.ignore.bind_addr to true Yes, I mean network interface not be specified as things seem to always work that way. And that leads to multicast setup not being so much error prone. Do you see any drawbacks of having that by default for JBoss AS 5? thanks View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4102240#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...