I am running a SBS2003 network and have several remote workers, all on XP-SP2 running Outlook 2003. We never used to have any problems before running an SBS2000 server with Outlook 2000. One of the users cant connect to Exchange server at all while the other can connect but will sometimes phone to say he cant. Internet and network drives are fine for both users over VPN. The client that cant connect is on BT broadband and the client that can is on BlueYonder. We have another remote worker starting soon and this problem needs to be sorted ASAP. It is really causing me a headache!!! I have tried reducing the MTU of the workers router from 1500 down to 1492 but to no avail. The IP address of our server is 10.0.0.1.