When JChannel members don't seem to find each other, then multiple solutions exist: the first is to check whether IP multicast is enabled. If this is the case, and the problem persists, try to increase the ip_ttl argument of the UDP layer (default is 31). This may be too small for WAN settings. Try to run the JavaGroups/tests/Mcast.java demo program to see whether the problem persists. If this program works, and JavaGroups doesn't, then the protocol stack is probably setup wrongly, e.g.UDP arguments mcast_addr and mcast_port are not the same in all group members.
If IP multicast is disabled, try to use unicast, as described above. Make sure that a gossip daemon has been started before starting any channels that use gossiping.
To see whether messages are received at all, insert a TRACE protocol layer just above the UDP layer, e.g.:
"UDP:TRACE:PING(gossip_host=janet.cs.cornell.edu;gossip_port=7879):..."
This layer prints all messages it receives from the network or from the layer above it. See section 4 for a discussion on how to write one's own layer, e.g. a modified TRACE layer which only prints messages received from the network, and does not print messages passed from the layer above.