Mystery of adding X500’s – What an amazing thing to know…!!!
This is something I learned this morning and thought I should share with my subscribers.
Issue:
Users are receiving NDR while responding to old emails of Ron Mayers.
Delivery has failed to these recipients or distribution lists:
Mayers, Ron
The recipient’s e-mail address was not found in the recipient’s e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try resending this message, or provide the following diagnostic text to your system administrator.
If you click on the name, the NDR will get resolved to:
IMCEAEX-_O=EXCH_OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FHSDHJF23GHYED+29_CN=RECIPIENTS_CN=RON+2EMayers@contoso.com
EXCH is the Exchange Organization name
Cause:
This behavior is caused because every internal message send/received in the orgn, will have the recipient info resolvable normally to the LegacyExchangeDN attribute. In this case, the user mailbox would have been recreated or the old LegacyExchangeDN value would have been changed to a different one.
Resolution:
We need to add a new X500 address to the user mailbox from Exchange Management Console. To do that, we need to first create it in the right format.
First step is to get rid of the _ and convert them to /
/O=EXCH/OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FHSDHJF23GHYED+29/CN=RECIPIENTS/CN=RON+2EMayers@contoso.com
Now the tricky part:
/O=EXCH/OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FHSDHJF23GHYED+29/CN=RECIPIENTS/CN=RON+2EMayers@contoso.com
Look closely and you see some numbers like +20, +28 etc… Wondering what they are?
+20 is a SPACE
+28 and +29 are ( and ) respectively
+2E is .
So the actual X500 address to be added will look like this:
/O=EXCH/OU=EXCHANGE ADMINISTRATIVE GROUP (28FHSDHJF23GHYED)/CN=RECIPIENTS/CN=RON.Mayers@contoso.com
I know it’s crazy but it is what it is… 
Update – MuthuKumar did cover X500 here:
Exmerge and X500.. A story…: http://msexchangeguru.com/2010/02/26/exmerge-and-x500-a-story/
Ratish Nair
MVP Exchange
Team @MSExchangeGuru.com
Keywords: Adding a new X500 address, Issue with X500 address, NDR while replying to old emails in exchange
March 15th, 2012 at 1:57 pm
This is a know issue becuase of the legacyexchangeDN being used by exchange to send internal emails. So you just need to add legacyexchnagedn of old user to the x500 of the new user with the same email id.
March 20th, 2012 at 3:03 pm
I have seen this in our environment as well, migrating from GroupWise to E2K10. For these users, I manually added the X500 address. My worry is that we have a migrtion coming up for two other sites that we e-mail alot with, on different versions of Exchange, and this will arise again. is there a bulk way to add these or do we don’t have to worry about it at all?
May 16th, 2012 at 5:59 am
Sahin,
I’m sure ADModify is the tool that you’re looking for!
Muthu
May 16th, 2012 at 9:31 am
Sachin,
Use this PS script on my article
http://msexchangeguru.com/2012/03/09/e2010-email-id-for-bulk-users/
October 11th, 2012 at 4:20 am
[...] http://msexchangeguru.com/2012/03/15/x500/ [...]
November 5th, 2012 at 2:29 pm
Adddition:
+40 represents @
November 8th, 2012 at 11:59 am
Addition:
+2C represents comma
+5F represents underscore
February 5th, 2013 at 7:03 pm
[...] http://msexchangeguru.com/2012/03/15/x500/ [...]