ADModify.net is an excellent tool for Exchange administrators allowing bulk changes of Active Directory properties.
I recently experienced the death of a power supply on an Exchange server, which set the clock ticking straight away. So to get users sending and receiving email quickly, I used ADModify.net to change the users mailbox location from the dead server to a spare exchange server. I also added the IP address to the spare exchange server. This got everyone sending and receiving real quick.
After recovering the hardware, I moved the users mailboxes back to the original server using ADModify as above. I then merged the mailbox data by mounting the databases used on the spare server in a recovery storage group and merging. Follow this tutorial by Henrik Walther to do that.
Here's how I did it:
Download ADModify and double click admodify.exe. Click "Modify Attributes".
From the drop down lists, select the domain you need to change properties and the Domain controller to use. You can then select the OU or User(s) you wish to change and click "Add to List", then select the user in the right hand window and click "Next".
To change the mailbox location, hit the "Exchange General" tab and simply select the appropriate server from the drop down lists of homeMTA and homeMDB.
Force active directory replication and send a test email to the mail box, and the user will now have a mailbox on the spare server. I use Email Generator to send test messages and check POP3, IMAP4 and SMTP connections.
Reverse the process to move mailboxes back and then merge the mailbox data collected while used on the spare server with the original data on the recovered server.
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