A common scenario for Exchange Server administrators is a customer that needs to change their primary email addresses to a new domain name.

For example a company that uses @exchangeserverpro.net as their email address might be acquired, or merge, or simply be rebranding to another name and wants to use @exchangeserverpro.com as their email address instead.

The Exchange Server administrator’s task is to:

  • Make the new primary email addresses of @exchangeserverpro.com begin to work
  • Make the previous email addresses of @exchangeserverpro.net continue to work

There are two features of Exchange Server 2007/2010 that need to be changed for this to happen.

Accepted Domains

The first feature is the Accepted Domains. This is the feature that tells an Exchange 2007/2010 organization which domain names it will accept mail for, and how to treat that domain name.

Accepted domains can be authoritative (ie, the organization owns the domain name and uses it for mail recipients) or can be a relay domain (ie, the organization will accept the emails but send them elsewhere).

There are a few other options such as shared SMTP namespaces but for the purposes of this scenario we’re just dealing with authoritative domains.

To add a new domain name to the organization launch the Exchange Management Console and navigate to Organization Configuration/Hub Transport. Select the Accepted Domains tab to view the current list of domains.

Exchange Server 2007/2010: How to Change the Primary Email Domain

In the Actions pane click on New Accepted Domain.

Exchange Server 2007/2010: How to Change the Primary Email Domain

Enter a Name and the Accepted Domain itself. The name can really be anything you like but most administrators just make it the same as the domain they are adding.

Exchange Server 2007/2010: How to Change the Primary Email Domain

Click New and then Finish to complete the wizard.

Note that if you have Edge Transport servers deployed in your network they will not receive the updated list of Accepted Domains until the next scheduled synchronization of the Edge Subscription.

Email Address Policies

Now that the new domain as been added as an Accepted Domain the next step is to configure an Email Address Policy.

Email Address Policies determine which SMTP addresses as are assigned to which objects in the organization, such as mailboxes, contacts, and distribution groups. Each organization has at least one Email Address Policy that by default will apply to all mail-enabled objects.

Here we can see mailbox users assigned with @exchangeserverpro.net email addresses.

Exchange Server 2007/2010: How to Change the Primary Email Domain

In the Exchange Management Console navigate to Organization Configuration/Hub Transport, and then select the Email Address Policies tab.

In this scenario we’ll just modify the default policy for all mail-enabled objects. Right-click the Default Email Address Policy and select Edit.

Exchange Server 2007/2010: How to Change the Primary Email DomainClick Next to skip past the introduction and conditions, until you reach the Email Addresses part of the policy. Click on the Add button.

Exchange Server 2007/2010: How to Change the Primary Email Domain

The Email address local part is an optional setting. If you do not specify one the Alias is used as the prefix of the email address. If you do specify one you can use the Alias or other combinations such as Firstname.Lastname.

Next type the domain name or click Browse to choose it from the list of Accepted Domains.

Exchange Server 2007/2010: How to Change the Primary Email Domain

Click OK once you have configured the new SMTP email address. Select the newly added SMTP address and click on Set as Reply.

Exchange Server 2007/2010: How to Change the Primary Email Domain

This will change the new address to bold, which means that it is the address that mail will appear to be sent from.  The other email addresses in the policy will allow people to continue to receive email sent to those addresses.

Exchange Server 2007/2010: How to Change the Primary Email Domain

Click Next to continue. Now we can choose when the updated policy will be applied to recipients. Usually this will be immediately, however you can choose not make the changes without applying the policy, or schedule it for a later time.

Exchange Server 2007/2010: How to Change the Primary Email Domain

Click Next, and then click Edit to complete the wizard. Depending on the size of your environment this may take some time to finish applying.

After the new policy has been applied you can see the change by refreshing the list of mailboxes. Notice that the primary SMTP addresses have changed from @exchangeserverpro.net to @exchangeserverpro.com.

Exchange Server 2007/2010: How to Change the Primary Email Domain

If you look at one recipient you can see that the new primary SMTP address has been applied by the policy, and the previous email address has been retained as well to allow mail sent to that address to continue to be received.

Exchange Server 2007/2010: How to Change the Primary Email Domain

You can see that after these tasks have been completed the organization has had the primary email domain changed to a new one while preserving the existing one at the same time.

About the Author

Paul Cunningham

Paul is a former Microsoft MVP for Office Apps and Services. He works as a consultant, writer, and trainer specializing in Office 365 and Exchange Server. Paul no longer writes for Practical365.com.


  1. ganeshprasad Pal

    Thanks , its help me still.

  2. ASA

    sorry, i want to ask out of the topic. i had microsoft exchange 2010, but i can’t send email to a domain, for the example the domain is *@gmail.com. where are the possible problem? but for the other domain there are no obstacles.

    thank you

  3. Ram

    Hi Paul,

    Thanks for sharing a lot of material and notes on EX 2016. I have a lab setup at home running EX2016CU10. So far everything is working fine with Public Cert.

    Just want to find out, if it is possible to configure multi domain within single Exchange 2016. Here is my lab setup.

    DC with AD on ramlan.ca
    Exchange Cert – mail.ramlan.ca
    Exchange 2016 fully configured
    GoDaddy MX and A record done
    Remote Connectivity Analyzer checked – all GREEN

    I want to include another authoritative domain into exchange which will be called infotechram.com. I have this domain at GoDaddy.

    What configuration, I need to perform on the exchange side to send and receive email for both the domains (ramlan.ca + infotechram.com) ?

    So far, I have completed the following:

    1. Created new authoritative domain in Ex 2016 (infotechram.com)
    2. Edited email address policies and added new authoritative domain under email address format

    Appreciate your help on the above.

  4. T800

    you talk about @practical365.com domain but in the pictures you are changing @exchangeserverpro.net to @exchangeserverpro.com?
    I can follow you but this is confusing a bit.

  5. NotSoTechyGuy

    Hi Paul,

    Currently we have an exchange server 2007 and using 123.com and wanted to change to abc.com on your guide above do we need to add new MX record and DNS record for abc.com? after that what will be the next step?

    1. Avatar photo
      Paul Cunningham

      Yes, you will still need to set up MX records for the new domain.

  6. EP

    Hi Paul,
    It is necessary to add the MX and CNAME record in the Public/Internal DNS?
    Thanks, best regards.

    1. Avatar photo
      Paul Cunningham

      MX records are necessary for other servers on the internet to be able to send you email to your domain, so they need to be added to public DNS.

      I’m not sure which CNAME record you’re referring to, but generally speaking you need to add DNS records to public DNS zones if you expect other hosts on the internet to be able to resolve that CNAME.

  7. NewTechie

    Hi Paul,

    Could I pick your brain on this problem please?

    We’ve recently moved from Exchange 2003 (domain “A”) to 2010 (domain “B”) with new servers too.

    When outlook 2010 opens for some of our users, it states “the server is unavailable” and if I click ‘work offline’ the wrong server is shown in the ‘general’ tab of the box that opens. It says “ExchangeSVR.a.internal” instead of NewExch.b.internal. For other users, it seems to work fine.

    My question is, how does the Outlook client know which server to go to when creating a profile for the first time? I’m guessing I need to make a change somewhere to remove the old server & domain entry, but would this be on the Exchange Management Console/Powershell or is it set when Outlook gets installed?

    Our users are still on Domain “a”.
    Our PCs and the new exchange server is on Domain “b”.
    ExchangeSVR no longer even exists.

    Should there be an entry in DNS on either domains for autodiscover, as I cannot find anything.

    If you need any further information, please let me know.

    Thanks in advance!

    1. Avatar photo
      Paul Cunningham

      Outlook uses Autodiscover to locate the server configuration options it needs to connect with. In your situation you’ll need to look into cross-forest Autodiscover.

  8. ajendra

    Hi Paul,

    I am facing some issue regarding Email Address policy, we have changed our smtp domain address earliar it was @tpc.com and now its changed to @cpl.com the problem is that we have added email address policy and that is replacting to upto 800 mailbox only after that its stoping not changing for rest of mailbox out of 3000,, and second one is how to apply changes for those mailbox whose having “unchecked box for automatically update email address” for some mailbox we have added manually smtp address other than standard address for other as “first name last name” but for these mailbox we have created there emails with different common name. so for these mailbox we are unable to apply the New Email address policy please suggest how to do that we are in middile in this activity.

  9. Niyas

    Hi, I am facing one problem, here we have several accepted domains.

    consider we have 123.com, abc.com, xyz.com etc, and have many mailboxes.
    some are having 123.com as primary SMTP some are having abc.com as primary SMTP and some are having xyz.com as primary SMTP.
    Now am in a situation that ONLY users having 123.com as primary SMTP need to be changed to abc.com as primary SMTP, no changes should happen to xyz.com, is there any way I can change it without going to every mailbox and change it manually, No idea how I will do it. It will take days to change all manually.

  10. Mahmood

    Do I need to change the CAS URLs? like Auto discover URL?
    Is the Outlook client going to use new domain or old one?

  11. Nino

    I have a question, which is related to changing the primary email domain however more to do with the Internal/External URL’s.

    We are already utilising the new domain name as the primary domain, however I would like to reconfigure all of the URL’s to the new domain also such as mail.olddomainname.com/owa to mail.newdomainname.com/owa, oab, autodiscover etc… now that I have purchased a new SAN certificate and can cover all of these URL’s.

    Is there an easy way to change these all in bulk, or do I just go through them all systematically ?

    For Exchange 2007.

    Thanks Paul!

    1. Nino

      Or, am I best to just go through the EMC GUI, and change them all via Server Configuration>Client Access ?


  12. Roger Fontaine

    Is there a way to do this in stages? Step 1, add new authoritative domain. Step 2, add new address policy so we can receive mail, but not change the primary address yet? Step 3, go back a couple days later and change the policy to update the primary? This would allow us to verify incoming mail and make changes to some mailboxes that don’t have the checkmark to update policy, etc. Thanks in advance.

      1. Roger Fontaine

        Perfect, Are there any instructions or help somewhere that might be available? Can you assist? Thanks

  13. Shyam Talke

    Hi Paul,

    I have gone through many blog sites and landed up here in search of solution to my query.
    We have Exchange 2013 environment where company.com is a default and is primary domain with Active Directory installed on same server. Few months later one new domain company2.in added as secondary in ecp. Now we need to place the company2.in as default and primary and make company.com as a discrete domain ( it may be possible through Multi-tenancy ). Simple words i dont want to have any relation with these two domains. How do i set Company2.in as my default and main ecp domain. Do i need to create new Active Directory for company2.com?

    Shyam T

  14. John Hoye

    Thank You Mr Cunningham, your documents and reddit posts and replies have done nothing but help me in my Exchange Administration experiences. If you have a book or t-shirts that I can purchase to support you, let me know 🙂

  15. Ryan

    Hi Paul,

    Great article, i just have a question. i have 1 domain and 1 exchange server i created additional 2 suffixes and those suffixes i also used when creating email. my problem is that the 2 suffixes i created can send email but cant received. what would be the problem?

    1. Avatar photo
      Paul Cunningham

      Explain what you mean by “can’t receive”? That’s a very general statement with a wide range of possible causes. Errors? What have you tried/checked so far to fix it?

  16. Vicky

    Hi Paul,

    Thanks for the article. I have to updated the change the Primary SMTP and add 2 more domains to about 2000 mailboxes for a client. But I have found that the option “Automatically update email addresses based on email address policy” is un-checked on all the mailboxes !
    I guess the policy won’t work right? So can be the option.
    Please advise.

    Many thanks


    1. Avatar photo
      Paul Cunningham

      Correct, without that option selected the email address policy won’t apply. You’ll need to either tick the box to let the policy apply, or run a script to manually add the addresses.

  17. Robert

    Hi Paul,
    Thank you for the tutorial. Since we’ve done this on our server everything seems to be working except for the Out of Office reply. Everyone is getting “Your automatic reply settings cannot be displayed because the server is currently unavailable” even though all other services seem to be working. Any ideas why this would stop after following these instructions? Thanks in advance!

    1. Avatar photo
      Paul Cunningham

      OoF can break when the EWS virtual directory URLs and the SSL cert on the server are misconfigured. Check that the EWS virtual directory has the correct internal/external URLs for your environment, and that the SSL cert on the server has those URLs on it. The Application and System logs on the server sometimes also yield clues about other possible causes.

  18. Mahmoud

    Hi Paul Have a good day from Egypt 🙂
    Firstly i would like to thank your for your always efforts and amazing articles.
    second i had made manually change for only two mailboxes users, One of our accepted domain being the default SMTP address and the old one as alias address, the problem is the outlook and mobile users must recreate a new profile to detect this change, otherwise they couldn’t able to send any message s.

  19. Maggie

    We did this and switched our primary domain. We have one recipient that we can send to all day long, but if they respond to the email they get a bounce back, with this error
    The following recipient(s) cannot be reached:

    Server error: ‘550 5.1.1 … User unknown’

    however, if they send to our OLD primary address, it goes through fine. Any insight? This is a great article. Thanks for sharing your knowledge.

  20. Stephen

    Thank You for the instructions, this worked great for us. I updated the email policy to reflect the new domain and that populated fine across the domain. How do you get the new domain to populate for Distribution list as well?

  21. Laurent

    Hello all,

    Please consider 2 different forests that share the same email domain.
    Considering that they do not want to set mutual relation ships (trust one each other), is it possible to share between them the free/busy service?
    For example: domA.com and domB.net share id@myLAN.org email domain.
    Can a user user1@domA.com share its free/busy calendar to user7@domB.com ?
    How can the ‘autodiscover’ domain run? (See: http://blogs.technet.com/b/msukucc/archive/2013/11/27/cross-forest-free-busy-in-untrusted-forests.aspx)
    With best regards


  22. Kristen Beechner

    I’ve read through your responses discussing auto replies to inform the sender of a domain change, and understand that you find them unnecessary. However, we were in litigation, and and will our domain at a certain date. I want to be able to send a one time response (because I agree it would be annoying to do it every time), to say as of this date blah blah blah… I see I have the ability in Office 365 to set up an organizational mail flow rule, but I don’t see anything to allow me to only send the rule once. Do you have any knowledge in the area?

  23. Gangaiyan

    Hi Paul,

    After changing the primary email address how do we address user outlook profile configuration which mean it’s still keep the old address name as top profile entry but we can recreate the profile in order to resolve but how can we do for all users? Please help me

    1. Avatar photo
      Paul Cunningham

      You have to recreate the profile. There’s no other way to change that as far as I’m aware.

  24. Bilal

    Would the Address Space tab under Send Connector require changing or the addition of the new domain. Currently we have our old domain , SMTP and Cost 1. Do I add the new domain to this list?

    1. Avatar photo
      Paul Cunningham

      Send connectors deal with outbound mail (one send connector for the “*” namespace is quite common) and usually would not require any changes if your own domain names had changed.

      1. Galeboe Mogotsi

        Guys! Thank you very much, this article helped me a lot…we have just implemented changing primary Email Domain and it worked wonders.

  25. rob

    is there a way we can do this via powershell script.

    1. Avatar photo
      Paul Cunningham

      Yes. Everything in Exchange can be done in PowerShell.

      There isn’t one thing happening in this article though, it’s multiple things put together. So creating the new accepted domain is one part of it, modifying the email address policies is another.

  26. Galeboe

    Thanks Man, it really helped.

  27. Galeboe

    What about the naming Conversion, what if it is not the same as the new domain?

      1. Galeboe

        I saw above example the email addresses are name.surname both for the new doamin and the old, what if your old doamin has name@domain.com and you want the new to be name.surname@domain.com?

  28. Galeboe

    What about the naming conversion, what if they are not the same?

  29. Andre Boom


    Change it with:

  30. Christian

    Hi Paul, thanks for sharing.

    Imagine an Exchange 2010 scenario with two accepted domains: aaa.com and bbb.com, obviously there’s only one default smtp address, aaa.com.

    Imagine an user with two smtp addresses, user@aaa.com and user@bbb.com, he can receive in his mailbox emails addressed to any of those two email address.

    Imagine sometimes that user needs to send using user@aaa.com and sometimes needs to send using user@bbb.com, there’s any chance to let that user choose outgoing smtp address? I’m thinking about create a couple of powershell scripts (user will execute aaa.ps1 or bbb.ps1 when needed), but it’s risky, user can make a mistake easily…

    Any idea?

    Thank you

    1. Avatar photo
      Paul Cunningham

      Exchange doesn’t natively support selecting a “From” address from the mailbox’s SMTP addresses.

      You can SendAs other mailboxes, distribution lists, etc though.

      1. Chris

        Thank you, I was expecting that answer…

        Default SMTP is not suposed to be a constantly changing feature.

        It would be sometimes an useful feature.


  31. Alejandro


    Quick question I hope. I am running Exchange 2013, CU2. For accepted domains, is this only for incoming mail? If I do the steps above, only email will be accepted for each user? I can’t change the outgoing FROM field in outlook to show the same alias and a different domain that’s being accepted?

    For my company it’s very important because we are legally doing business as 1 name as well as the principle name. So do I need to setup a second exchange server? Or use a different mailbox for the different accepted domain?

    It’s weird because I sign into exchange with foo@domain1.com domain and it logs in, dls the email messages. Then When I change the from field to foo@domain2.com it works but foo@domain3.com does not work. It’s weird that it’s working for some and not others. I wonder what exchange does to determine to allow this or not.

  32. L Batchelor

    Hi Paul,

    Thanks for excellent article.

    For testing the smtp send by just 1 user can you configure the new accepted domain, add the new email policy but not apply the policy with “set as reply” for the new domain? ie leave existing domain as bold and default for email policy and use new domain as a usuable option but not the default “set as reply”.
    Not sure if you apply policy and just do not assign “set as reply” for the new domain.

    Can you then reconfigure 1 user in user email properties and change their “set as reply” to the new domain whilst the rest keep using the old domain until you apply policy for all users?

    Thanks in advance

  33. Ira

    Hi Paul. Great article. I will be changing the primary domain name on an Exchange 2010 server per your steps. We have a number of iphone and android phone users getting their exchange mail via the active sync exchange account on their phones. What will be the impact on these phones after the primary domain name change on Exchange? Will we have to re-create all these phone email accounts?

    1. John P


      We’re about to make these changes next month. What was the impact you experienced? Do we need to prepare documentation for users to update their Activesync devices or will it go smoothly?

  34. Yves


    We have just done whats been discribes in this article. We moved from .be to .com Now since we have done that i get alot of complaince that people cant send mails to us getting a message back like this:

    Diagnostische gegevens voor beheerders:

    Server: XXX.ABC.be

    mail.OurDomain.be #554 5.7.1 This message has been blocked because the HELO/EHLO domain is invalid. ##

    Are there any other setting i need to reconfigure to make the work?

    1. Avatar photo
      Paul Cunningham

      Look at the properties of your Send Connector. The FQDN used for HELO/EHLO must be externally resolvable. If there’s nothing configured there it will just use the name of the server. Either way, it has to be externally resolvable in DNS or a lot of servers will reject your mail.

      1. Yves

        Thanks for the reply.

        There is a FQND thats externaly resolvable. I found the problem. It was our firewal that was checking HELO/EHLO after i did an upgrade of the firmware. Did some changed there and everything is working just fine again!

  35. Freddy


    Great news, it works now. And as you told it, it was a stuff with the MX record. The solution to make it work was to add the ip public address oh the old domain on the new domain as a A record. And voilà … it works. I can send and receive from inside/outside office, on BB phones, on ipad, iphone, ANdroid tabets and phones.
    Thanks for your ideas on my problem !!

  36. Andre Boom

    Don’t want to come between you guys but:

    Could it be that you have a 3th party spam filter between your mailbox server and the internet?
    Some spamfilters require that you add a domain and a forward address. Could it be that you missed/skipped this part?

    1. Freddy

      Hi Andre,

      Unfortunately I don’t have things like that (spam filter) on my mailbox server.

  37. Freddy

    Hi Paul,

    I set a new accepted domain on my exchange 2010, in authoritative mode. My users on this accepted domain CAN SEND mail to internal and external mail adresses , also can receive mails from exchange users, but CAN’T RECEIVE any mails from internet.

    Can you help me ?

      1. Freddy

        Yes, for sure. I’ve add mx on my dns server role. And that’s why I can send mails. And I can telnet my server.
        But receiving from internet is not possible. However I don’t reveine any error report from yahoo or gmail. It seems like the mails are well delivered.
        What I do is put a new UPN ( the same as the new accepted domain) and create new mailbox directly with this new domain. In the properties oh this user, his mailbox adresses are first the new domain one as default and the old domain (the active directory one) is the second mailbox

        1. Avatar photo
          Paul Cunningham

          The MX record isn’t involved in you sending email, only receiving.

          Without knowing your domain name there’s not much else I can suggest other than you should go to mxtoolbox.com and start running tests.

  38. Josh

    Hey Paul,

    Great article. Is there a way in exchange 2010 to workaround having to manually create security groups in AD for users who want to receive from mulitple authoritative domains as well as send from these domains?

    Primary abc.com
    Secondary def.com
    Tertiary xyz.com

    They can receive mail using this method, however, is there an easy way so the users can send out from Outlook using the domain of their choice? In the past we have setup AD security groups and manipulated them with the secondary accounts so outlook could send using that account. Make sense?


    1. Avatar photo
      Paul Cunningham

      No, users still can’t choose from multiple email addresses on their own mailbox when sending. They can only Send As another mailbox or group.

  39. Raj

    You’re is just MARVELOUS . Thanks for sharing knowledge.

    Need another help. Is there any way to find out which admin has accessed which users mailbox. I suspect few our exchange administrator not following their ethics and i want to trap them..

    Appreciate your help.

  40. Jeff

    Hi. We have an issue with meeting requests after the primary smtp address is changed. The attendee is not receiving updates for an existing recurring meeting after their primary smtp address was changed. When viewing the recurring meetings I would see the user listed twice, once with their old address and once with their new one. When the meeting organizer sent out changes they did not receive them. Any thoughts? Thanks.

    1. Avatar photo
      Paul Cunningham

      Did the old email address get retained on the mailbox as a secondary email address?

      1. Jeff

        Yes, it still is an alias on the mailbox. Could it be related to a missing x500 address?

  41. mk

    My default accepted domain is yyy.com and primary smtp address is user@yyy.com.
    When i send email for external/internal users using OWA then address from is user@yyy.com, but using imap client mail come from address xxx.com.
    I found that when i change mail address on imap client server configuration to user@yyy.com then everything is OK.
    Probably i have to use address rewrite agent on my Hub Transport Server using

    1. Avatar photo
      Paul Cunningham

      Yes, IMAP clients can specify their own “From” address independently.

  42. mk

    I have problem. I have 3 domains 1 old one and 2 new one’s. I can reseive masseges from all 3 domains. My primary mail address is changed correctly to @yyy.com, but when i sent mail using imap client like Thunderbird and leave old address as from (@xxx.com), then mail come to external or internal mailbox with old address not (@xxx.com) not default new one (@yyy.com). When I use OWA the from address is setup as new address and there is no problem

    1. Andre

      Change the default accepted domain to the new one.
      set the correct primary smtpaddress
      get-mailbox USER | set primarysmtpaddress user@yyy.com

  43. Andre Boom

    Hi Paul,

    Thanks for the great instructions, much appreciated.
    Would you be able to confirm if I can delete the old domain later on and if the users are able to use the new domain to log to on Outlook Web app?

    I had 123.org
    I added 456.org
    Is the user john able to log on to OWA on the new domain name ( 456.org ) and can I delete the old (123.org ) domain?

    1. Avatar photo
      Paul Cunningham

      Their OWA logon will be their UPN, not email address. UPN has a similar format to email addresses, but is a different account attribute.

      If you change their UPNs to match their new email addresses, then they can use the new one to login.

      I generally don’t remove the old domains, unless it is a specific reason to, because you never know who might try to send them email to their old addresses for years to come.

  44. Alan Lumley

    Thanks Paul,

    This is putting a show stopper on my migration.

    1. Avatar photo
      Paul Cunningham

      Well at best I can try to reproduce it to see if you’re alone or not. But if its a bug that needs fixing you’ll need to raise a support case with Microsoft anyway.

      1. Alan Lumley

        Thanks, Paul

        Let me know if you find anything please.

  45. Alan Lumley

    This has worked, very good work and thanks very much for documenting the process, Paul.

    However I do have a small snag.

    In the interim of the changeover for all external contacts getting used to using the new email address, when the execs are receiving emails with multiple recipients to their old domain email address and try to do a reply all.

    They are automatically CC’ing themselves into the reply due to the primary send mail address being the new domain email instead of the prior one.

    Is there a way we can rectify this issue as it has put a halt on the migration.



    1. Avatar photo
      Paul Cunningham

      And that only started when you changed their primary email addresses? I haven’t seen that behaviour before, and its not reproducing for me in my test lab.

      1. Alan Lumley

        Hi Paul,

        Managed to pinpoint that it is only happening on Outlook 2011 on the MAC books.
        Outlook on the Windows clients have been clever enough to realise the 2 domains for one user is the same person and this does not cause any confusion.

        1. Avatar photo
          Paul Cunningham

          Oh okay. Case closed then 😉

          I’ll try and repro with a Mac and see what happens. Interesting bug if it is one.

  46. Samir

    Great Article !
    Recently, we had changed the primary address of users but this new address does not appear in outlook of clients. I have no problem with OWA it works fine

    Any suggestions.

    1. Avatar photo
      Paul Cunningham

      You mean at the top left side of Outlook where the mailbox name is displayed?

      1. Dawn

        Hi Paul,
        I’m having the same issue. We changed primary domain – but on the outlook client, the account is still displaying the old domain name. The top left where the mailbox name is displayed, and if you go into account settings, the mailbox name is still the old, and I can’t change it. Any suggestions without having to remove the mailbox and add new?

        1. Avatar photo
          Paul Cunningham

          From what I can see that display doesn’t update without recreating the profile (you would want to test that though to be sure, before you go recreating everyone’s profiles).

  47. Jim Satterfield

    I am setting up a new Exchange server and we have multiple domains. In my testing I have set up authoritative accepted domains. I can configure it so that a user receives from multiple domains without any real problem. Is there a way for me to configure users who deal with more than one of these domains to be able to send email from an email address of their choice?

    Example: A customer service person provides support to both ABC Company and XYZ Limited. When they contact someone dealing with ABC they need to send from customerservice@abc.com and when dealing with a customer of XYZ they need to send from customerservice@xyz.com. I haven’t figured out how I can set this up yet and need an answer. Thanks in advance for any help anyone can provide.

  48. Alastair

    We have already got a second accepted domain that was set up a while a go. I am trying to switch this second domain to being the primary so that the the sent email uses this domain name. (while still recieving emails on the original) neither is the domain for our site.

    When I changed Hub Transport – email policies – Default policy – as the second domain was already there I set it as the default. It updated but in Recipient Config – Mailboxes the Primary SMTP Domain had not updated.
    Do you think this is a time issue or Transport Role restart issue ?

    Also In Hub Trans – Accepted Domains how does changingthe accepted domain default to the new one change things ?

    Finally we have one Send Connector – however the FQDN now points to the original domain and not the new one.

    I have a SSL certificate attached to the original domain but am happy keeping the OWA on this address at present.
    Thanks !

  49. IT-Consulting

    What about setting a rule, that informs the sender with an automatic response that the address he sent the email to, is not used anymore. (emails to the old address will still be forwarded to the new account).
    is there any solution to do this on a exchange server? transport rules?

    Thanks ?_)

    1. Avatar photo
      Paul Cunningham

      To be honest those types of auto-replies annoy the heck out of me. My view is that an address should either be silently accepted (eg as a secondary address on the mailbox, or by forwarding it wherever it needs to go), or otherwise it should hard bounce.

  50. Rasheedah

    hi paul,

    Great article(s) as always. I have situation similiar to this. I have 2010 installed in a 2003 exchange org. nothing has been moved over yet.

    the company wants to re-brand their email prior to migrating to 2010. the current mx record is abc.com. they want abcd.com. here is what i am thinking that needs to be done.

    1. add abcd.com mx record.
    2. add policy on exchange 2003 moved this to high priority
    3. re-do the cert but since this is for exchange 2003 how should this be done?

    i am not sure what needs to be done for external access it is webmail.abc.com but now needs to be webmail.abcd.com.

    Once this is done this should update in exchange 2010 automatically, i think.

    Please advise?


  51. Ernesto

    Hi Paul,

    What about client side? I need to recreate the profile?

    thanks in advace


  52. Jim Sutherlin

    Since our exchange server requires SSL, do I need to obtain a new certificate with the 2nd domain added to it or would the authentication still happen with the “old” domain?


    1. Avatar photo
      Paul Cunningham

      You’ll only need a new SSL cert if you change the external URL for services such as OWA.

  53. DCRG


    I have recently carried out the above to add a new accepted domain, and set it to be the reply address whilst leaving the original domain intact so external users can still email people on the old email address. is there a way to send an automatic reply to messages that are addressed to the old domain, whilst still ensuring the user receives the email message?

    I have had a play with Transport rule and selected the reject email message when the recipients email address contains XXXXX (the old email address) with a response of “blar blar blar” but this does not have the required results….

    Any help would be appreciated

    Any help would be appreciated

    1. Avatar photo
      Paul Cunningham

      I’ve never really looked into this because I’ve never seen the need for it. The whole point of this config is so that mail can still be received on the old addresses but new mail is sent out to the new addresses.

      In my experience it is a situation that just naturally sorts itself out over time. The number of emails sent to the old domain name slowly diminishes.

      Is it that critical for you that you absolutely need to do it?

      1. DCRG

        Hi Paul,

        Thank you for the reply.

        I agree completely and this is the first time i have ever looked into this for that very reason.
        I have been asked the question if this is possible to speed up the time it takes for external senders to start using the new email address.
        I have researched this for a few days and cannot find a suitable way of doing this?
        obviously Auto replies could be used, however this would be impractical as users would not be able to set their own OOF when needed.

        So im stuck really, if you have any ideas that would be great, if i ever get to the bottom of this i will update post…


      2. Avatar photo
        Paul Cunningham

        Somebody subscribed to my newsletter list does this by the way. I get a “We’ve changed email domains” email every week when I send out the newsletter.

        It’s pretty annoying to be honest, since there is nothing I can do about it. They’ve signed up with that email address, I can’t change it to the new one for them 🙂

        Put yourself in the sender’s shoes… do they want to receive that auto-reply? Probably not. As long as their mail is getting through they probably don’t care 😉

      3. Christine Uzamukunda

        Hello Paul,
        I have changed the domain name, now i can send emails from exchange but i cannot receive emails send through old address or new address from yahoo email.

        1. Avatar photo
          Paul Cunningham

          There are many things that can cause mail to not work. I recommend you look at exrca.com and do the inbound mail flow test to get started.

    2. Dan

      If it were up to me, I’d be happy just accepting mail on the new domain. But our management wants to send out an error message and accept the mail at the same time.

      We’re looking at the “send bounce message to sender with enhanced status code” option in hub transport, but it doesn’t look very promising. We can’t get it to trap on inbound messages send to the old domain name.

  54. Brian Singer

    Is there any re-configuration necessary on the client side (Outlook)?

    1. Avatar photo
      Paul Cunningham

      Hi Brian, nothing needed for the Outlook users. Except I guess maybe updating their signature 🙂

      1. Royal Wang

        I have one problem,

        i have 2 email address, one is primary SMTP@123.com and the other is alias@321.com
        first to say, i can receive the eamails from there 2 mailboxID
        due to business pruposes, i sometimes send emails with my alias as @321,but always failed.

        1. Avatar photo
          Paul Cunningham

          Exchange doesn’t allow you to send from an alias on your own account. You’ll need to move that address to a different mailbox (like a shared mailbox) and configure SendAs permissions, or set it up as separate user mailbox and configure both accounts in your Outlook profile.

          1. ozgur

            Hi thank you great information ..
            I need solution which is i have xx.aaa.com mail server and only use send email,

            But I need all mails sendin like aaa.com. is it possible like this..
            what can ı do.
            Thank you

  55. saleem

    thanks for valuable info..
    1) i did the same added new accepted domain abc.test.com
    applied a new mail box policy and the existing email addresses changed to abc.com
    and i can send and receive mails from internet with out any problem,.

    2) i added 3rd accepted domain and applied email address policies
    and i can send and receive mails to the 3rd domain xyz .com
    now i want to apply policies to the 3rd one so that mail will be delivered to only some of them in xyz.com
    any idea ?


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