Question : Mrigrating from Exchange 2003 to Exchange 2007

Can you point me to some step by step instructions for migrating to Exchange 2007? I have setup a new x64 Server. What happends when I do AD prep? Will this still make it possible to have exchange 2003 working. Then I plan on just changing the IP address on my servers to have the MX record point to my exchange 2007 server. Should I move the database to the 2007 server or move mailboxes. Maybe you can point me to some best practices.

Answer : Mrigrating from Exchange 2003 to Exchange 2007

This is the documentation i use
http://technet.microsoft.com/en-us/library/bb124008(EXCHG.80).aspx

For a single domain here is more info
http://technet.microsoft.com/en-us/library/aa997617(EXCHG.80).aspx

OK Step By Step
http://searchexchange.techtarget.com/generic/0,295582,sid43_gci1303894,00.html

Step by Step for Moving Mailboxes and public folder info
http://searchexchange.techtarget.com/generic/0,295582,sid43_gci1302950,00.html

When you do an Ad prep it adds all the new fields of EX2007 to your active directory database. Exchange 2003 will still function afterwards. I would move you mailbox's not your databse. There is a move mailbox tool in 2007 thats works nicely for an average size exchange server (less than 1000 mailboxes). If you have more than 1000 mailboxes there are some nice scripts available to move the mailboxes.

I wouldn't change the IP address of your 2003 server you can manually change the MX record. Your outlook 2007 clients will autodiscover their new server using the autodiscover dns entry  (for the server ip) and AD for the mailbox itself your other clients will just need to be repointed to the new exchange server name.  If you have multiple sites specified in AD Microsoft requires you to have a client access role in each site. Remember you need a full exchange server license even if you install just one role.

Here is a good Doc if you have multiple AD sites http://technet.microsoft.com/en-us/library/aa996299(EXCHG.80).aspx

Hope this helps