I have an intermittent problem connecting Outlook 2007 to an Exchange 2003 server over my VPN. I always use a hosts file on the computers and most of the time it works fine. However, sometimes it does not. The problem appears when I hit the "check name" button and it fails to resolve the user. I have this problem about 25% of the time when I try to connect this way. Outlook 2003 never has a problem synchronizing over the VPN to the Exchange server.