Unity Connection Cluster Installation Failure – UDP Fragmentation

I found an interesting fact about an Unity Connection Cluster. During installation if a subscriber node cannot send an unfragmented packet the size of the mtu to the publisher the install will not complete. My customer has a new AT&T Gigabit link between his new UCN cluster and the subscriber install kept dying on “Connection Validation” it finally error out saying that it could not send UDP packets to the publisher. I tried to ping the other end with the do not fragment bit set with a size of 1500 bytes and that failed but a 1450 byte ping would go straight through (actually up to 1472 would work). I changed both servers to 1450 mtu and the install completed without any issues. Just a FYI.

– Andrew