At my job I'm in the process of migrating our Exchange 2003 server from one HP server to another. I did some testing with my email account and found that the iPhone integration stops working when I move my mailbox from exchange01 to exchange02. The way things are setup the MX and A records point to the public IP address which is assigned to our Barracuda spam box, and from there it forwards it to Exchange01. Exchange01 will then check and see which server the mail is on and work accordingly. So mail works fine, Blackberry phones work fine. However iPhones don't work at all. The mail server that the iPhones point to originally is mail.alsformalwear.com, however the new mail server is called exchange02.alsformalwear.com. The migration is going to take a few days with all the replication and getting everything moved over. Once it is done I will be uninstalling exchange01 and then renaming exchange02 to exchange01 and changing the private IPs to the IPs that were on Exchange01, so after all that it should be the same and hopefully the iPHones will start working again. I'm trying to find a way however to keep them working during the migration as most of our iPhone users are VPs and would like to have continued access. Is there something I should do to get the iPhones to work on both servers at once?