jgroup members can't join?

I use a ehcache that distributes via jgroups. I use UDP multicat for the distribution.

The ehcache lives within a webapp. There are several machines that run that webapp. For some reason I get a WARN NAKACK. Seems that the several instances of the ehcache can't join to a jgroup.

This is the ehcache config (containing the jgroups-config):

<cacheManagerPeerProviderFactory        class="net.sf.ehcache.distribution.jgroups.JGroupsCacheManagerPeerProviderFactory"
    properties="connect=UDP(mcast_addr=${ehcache.multicast.address};mcast_port=45566;ip_ttl=32;
        mcast_send_buf_size=150000;mcast_recv_buf_size=80000):
        PING(timeout=2000;num_initial_members=6):
        MERGE2(min_interval=5000;max_interval=10000):
        FD_SOCK:VERIFY_SUSPECT(timeout=1500):
        pbcast.NAKACK(gc_lag=10;retransmit_timeout=3000):
        UNICAST(timeout=5000):
        pbcast.STABLE(desired_avg_gossip=20000):
        FRAG:
        pbcast.GMS(join_timeout=5000;join_retry_timeout=2000;
        shun=false;print_local_addr=true)"
    propertySeparator="::" />

This is the stack trace:

TRACE - UDP                        - received [dst: <null>, src: testforce-54850 (2 headers), size=0 bytes, flags=OOB], headers are PING: [PING: type=GET_MBRS_REQ, cluster=EH_CACHE, arg=own_addr=testforce-54850, view id=null, is_server=false, is_coord=false, logical_name=testforce-54850, physical_addrs=fe80:0:0:0:216:3eff:fea6:7808%2:35176], UDP: [channel_name=EH_CACHE]
TRACE - PING                       - received GET_MBRS_REQ from testforce-54850, sending response [PING: type=GET_MBRS_RSP, arg=own_addr=hitchhiker-12009, view id=[hitchhiker-12009|0], is_server=true, is_coord=true, logical_name=hitchhiker-12009]
TRACE - UDP                        - sending msg to testforce-54850, src=hitchhiker-12009, headers are PING: [PING: type=GET_MBRS_RSP, arg=own_addr=hitchhiker-12009, view id=[hitchhiker-12009|0], is_server=true, is_coord=true, logical_name=hitchhiker-12009], UDP: [channel_name=EH_CACHE]
TRACE - UDP                        - received [dst: <null>, src: testforce-54850 (2 headers), size=0 bytes, flags=OOB], headers are PING: [PING: type=GET_MBRS_REQ, cluster=EH_CACHE, arg=own_addr=testforce-54850, view id=null, is_server=false, is_coord=false, logical_name=testforce-54850, physical_addrs=fe80:0:0:0:216:3eff:fea6:7808%2:35176], UDP: [channel_name=EH_CACHE]
TRACE - PING                       - received GET_MBRS_REQ from testforce-54850, sending response [PING: type=GET_MBRS_RSP, arg=own_addr=hitchhiker-12009, view id=[hitchhiker-12009|0], is_server=true, is_coord=true, logical_name=hitchhiker-12009]
TRACE - UDP                        - sending msg to testforce-54850, src=hitchhiker-12009, headers are PING: [PING: type=GET_MBRS_RSP, arg=own_addr=hitchhiker-12009, view id=[hitchhiker-12009|0], is_server=true, is_coord=true, logical_name=hitchhiker-12009], UDP: [channel_name=EH_CACHE]
TRACE - UDP                        - received [dst: <null>, src: testforce-54850 (3 headers), size=0 bytes, flags=OOB], headers are GMS: GmsHeader[GET_DIGEST_REQ]: mbr=null, NAKACK: [MSG, seqno=30], UDP: [channel_name=EH_CACHE]
TRACE - NAKACK                     - hitchhiker-12009: received testforce-54850#30
WARN  - NAKACK                     - hitchhiker-12009: dropped message from testforce-54850 (not in xmit_table), keys are [hitchhiker-12009], view=[hitchhiker-12009|0] [hitchhiker-12009]
TRACE - STABLE                     - hitchhiker-12009: setting latest_local_digest from NAKACK: [hitchhiker-12009#3]
TRACE - STABLE                     - hitchhiker-12009: sending stable msg [hitchhiker-12009#3]
TRACE - NAKACK                     - sending hitchhiker-12009#4
TRACE - UDP                        - sending msg to null, src=hitchhiker-12009, headers are STABL开发者_StackOverflow中文版E: [STABLE_GOSSIP]: digest is hitchhiker-12009: [0 : 3 (3)], NAKACK: [MSG, seqno=4], UDP: [channel_name=EH_CACHE]
TRACE - UDP                        - looping back message [dst: <null>, src: hitchhiker-12009 (3 headers), size=0 bytes, flags=OOB]
TRACE - UDP                        - received [dst: <null>, src: hitchhiker-12009 (3 headers), size=0 bytes, flags=OOB], headers are STABLE: [STABLE_GOSSIP]: digest is hitchhiker-12009: [0 : 3 (3)], NAKACK: [MSG, seqno=4], UDP: [channel_name=EH_CACHE]
TRACE - NAKACK                     - hitchhiker-12009: received hitchhiker-12009#4
TRACE - STABLE                     - hitchhiker-12009: handling digest from hitchhiker-12009 (0 votes):
mine:   [hitchhiker-12009#2]
other:  [hitchhiker-12009#3]
result: [hitchhiker-12009#2]

Any ideas what I can do about this? Thanx

Your post is half year old now, anyway, in such a case you have to make sure that the servers are in the same physical network and the port that you use for udp communication is not blocked anywhere between them.