UDP issue

[mikefinn]

I am confident this is not a JBoss or JGroups issue, but was hoping someone here may have seen this before. JBoss 4.0.3SP1 + RHAS 2.1 + Sun JDK 1.5.05. We have two cluster nodes (same subnet) that aren't finding each other. MCast and port are right on each box. I used jgroups probe util and in fact the only server that shows each is the 'local' one. So, I have been using the jgroups sender (McastSenderTest) and receiver (McastReceiverTest) utils, combined with ethereal to watch the traffic.

The receiver will only get the first 1 or 2 things I type into sender. But, ethereal shows every one I typed as going out. So, if I type 10 messages, recv will get #1 and #2 (or sometimes just #1), and ethereal shows all 10 going out. If I wait a few minutes and try again, it'll do the same thing.

Our network group is watching at the switch and sees the same thing that the 'receiver' does (gets first two packets, but no more). Weird? Anyone have ideas?

I suppose if this doesn't get fixed soon (causing our distributed caches to be not-so-distributed), I will need to go to IP for all svcs that use jgroups.

TIA,
Mike

[belaban]

Hard to diagnose - could be a firewall problem on the sender, buit then I would assume *no* packets gets through at all

[mikefinn]

Thanks for the reply. Turns out our two nodes were actually plugged into two different switches. Somewhere in the path between them, "some" packets were getting dropped. Scary. This should work (provided no routers in the way). Got both boxes plugged into same switch, all is now working.

Thanks again,
Mike