We have recently noticed that we are seeing delays between our European email server and Australian one both running E2K7 SP1. Research showed this was due to a number of large public folder messages up to 100Mb in size. Seemingly what happens is that these messages fail with a 421 4.4.2 Connection dropped error and only then do the other small messages get delivered.
Can anyone assist with how to fix this issue. Workaround is currenlt yo to suspend the large messages and restart the transport service.
Network is a MPLS WAN with up to 6Mbps of capacity available.