Running Exchange 2007 SP2 and Outlook 2007 SP2. Had some questions about LegacyExchangeDN. 1. Is this value used by Outlook for all mail objects (DL email address, mailbox addresses, Contacts etc)? 2. Let's say I have a user with email address john.doe@domain.com. His username is Domain\JohnD. His Alias is JohnD. I delete his mailbox and then recreate it again a week later. Will the LegacyExchangeDN value still be the same? 3. For the example above, after the mailbox is recreated will users still be able to email him using Outlook cached entry? 4. Does Outlook cached entry always use LegacyExchangeDN? Or is it for replies or new messages using cached entry only? Thanks in advance!

You posted related question here http://social.technet.microsoft.com/Forums/en/exchangesvrgeneral/thread/545bba7f-5997-4dd5-97ee-30224aa46120 1. Yes 2. Yes if alias is the same 3. Depends, the user may have had historical legacyExchangedn's from previous migrations which get set as x500 addresses. When you delete the mailbox and recreate those historical x500 addresses are lost. So if someones replying back to an old email that was using an old legacyexchangedn from previous migrations then it will fail 4. Yes outlook stores the cache in x500 format not smtp.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Thanks for the answers. 1. Thanks. 2. So the LegacyExchangeDN is derived from the Alias? We need to ensure the Alias is always the same if we recreate a deleted mailbox? 3. Is there a way to find out which LegacyExchangeDN's the user is emailing? We can then add that one. 4. Great, but does Outlook use the X.500 address for replies only, or when composing a new email (but still using the cached entry), or both?

2. Yes it uses the mailnickname (alias) attribute /o=MyCompany/ou=MyAdminGroup/cn=Recipients/cn=MailNickname How the Recipient Update Service applies system policies http://support.microsoft.com/kb/253838 3. Once you delete the account all settings are gone so you can't really reference it to get it back. Typically when the user sends the email and gets the NDR then you know its missing and from the NDR you can determine the x500 address. the NDR is not in the user frieindly verbatim format so users typically still ask questions on exactly what format to enter. You can also use nk2edit a free tool to and copy the nickname cache file from the user whos trying to send and open it up. From there you can see the x500 addresses in user friendly format. Example screenshot below. http://www.nirsoft.net/utils/outlook_nk2_edit.html 4. Only replies because, if the user previously sent to some that addresses is cached and stored in the nickname cache. When creating new emails its not in the cache so it uses SMTP.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

On #4, I'm still a little confused. Let me give an example - about 1 month ago I a user sends an email to john.doe@domain.com. This entry is now cached in his Outlook. Does this cached entry use the X.500 address associated with John's account? So whenever he uses that cached entry - doesn't matter if he's replying to a mail from John or composing a new mail to John THAT USES THE CACHED ENTRY ADDRESS RATHER THAN LOOKING IN THE GAL, wouldn't the X.500 address be used? Thanks for the help, really appreciate it!

Yes correct once he sends to john replies ore new emails to him will be using the x500 address.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Let me give an example - about 1 month ago I a user sends an email to john.doe@domain.com. This entry is now cached in his Outlook. Does this cached entry use the X.500 address associated with John's account? So whenever he uses that cached entry - doesn't matter if he's replying to a mail from John or composing a new mail to John THAT USES THE CACHED ENTRY ADDRESS RATHER THAN LOOKING IN THE GAL, wouldn't the X.500 address be used? Once you send mailt to a user, Outlook2007 or Outlook 2010 automatical save his X.500 address into NK2 file. When using the outlook autocomplete function, Outlook2007 or Outlook 2010 use the X.500 address from NK2 file. More information about NK2 file http://office.microsoft.com/en-us/outlook-help/copy-autocomplete-name-list-to-another-computer-HA001139451.aspx Here are some information may help you . Just what is your address? http://blogs.technet.com/b/exchange/archive/2004/03/24/95451.aspxPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.