Impact of Changing a User's SIP Address

If the left-hand side of your users’ SIP addresses contain a common user attribute in Active Directory such as first name, last name (or both), there is a good chance that the SIP address will need to be updated to match any corresponding change to the user attribute(s) in AD.

The thought of changing an important attribute like the SIP address made me a bit uneasy and wondering what the impact would be. Specifically, after the SIP address change, would communication still work with another Communicator user who had previously added the old SIP address into their contact list?

After being involved in a deployment that did a few SIP address changes, I am pleased to report that there were no major issues. The seamless communication is made possible by OCS storing user contact lists by unique-id instead of SIP address. Here are some important points to consider however:

  1. One of the biggest issues that could arise is that Office Communicator integration with Outlook will break if the user’s SIP address does not match the primary SMTP email address in their Outlook profile (see previous post “Office Communicator 2007 and Outlook 2007 Integration Errors”), so the primary email address will need to be updated to avoid this error. If you do update the primary email address to match the new SIP address, ensure that the user’s Outlook profile gets updated. The Microsoft Exchange Autodiscovery service can auto-update the profile if you have Exchange 2007 or 2010 deployed.
  2. Users will need to restart Communicator after the SIP change. Outlook should also be restarted to ensure integration functions correctly.


  1. A reader of this blog tried a change to the right-hand side of the SIP address (the domain portion) and it did not work (see the comments below).
  2. The SIP address change was not tested with the OCS Group Chat functionality. If anyone has experience with this, your feedback is appreciated.

July 2013 Update: see the blog post Anatomy of a SIP Domain Change ( for more information on this subject as it relates to Lync server.

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16 comments to Impact of Changing a User’s SIP Address

  • Justin

    Ah, cheers Curtis, much appreciated!

  • Yes. You can remove the mailbox but IM will continue to work as normal – as long as you don’t remove the underlying AD account!


  • Justin

    Ah, thanks a ton Curtis, that helps a lot. I’m not overly familiar with OCS so appreciate the info. Just to clarify – if a mailbox-enabled exchange 2010 user who is enabled for OCS 2007 suddenly has his or her mailbox removed, IM would continue to work as normal?

  • Hi Justin,

    I think you might be confusing the Exchange and OCS functionality. The IM and Presence functionality is sourced 100% from OCS 2007. Exchange/Outlook just integrates with OCS to provide IM and Presence.

    All SIP addresses need to have a domain (e.g. If you want the OCS Presence and IM functionality to work in Outlook, the SIP address needs to match the primary email address in the Outlook profile.

    Hope that helps,

  • Justin

    Hi, i know this thread has been inactive for awhile, but i have a question that hopefully someone can answer. Is the IM functionality of OCS 2007 dependent on the presence of an exchange mailbox? i.e. if it was just the AD account, and the SIP was set to something like first.last@ or SAMAccountName, would IM work? IM is the only requirement for this scenario; obviously I wouldn’t expect Outlook integration to work.

    Thanks in advance!

  • Hi Howard,

    Yes, if the SIP is different from the SMTP address in the default Outlook mail profile, integration won’t work.


  • Howard

    If the SIP is different from the primary SMTP address, outlook integration won’t work. Is that correct?

  • I hadn’t tried a SIP change in a Group Chat environment so thanks for the feedback. That is odd that the behavior was different for some users and not others…


  • Brandon

    After doing our final change, we were able to test Group Chat and it was strange. It worked for about 90% of users and then the other 10% could login, but couldn’t join chat rooms. It removes everyone’s previous chat rooms they had listed, but they could easily add them back and join them – except for these small users. It ended up being a reboot of the Group Chat server (possibly restart of services may have worked) that fixed all of them. They would show up as members in the group, but it would show their “old” sip domain address in there. I had investigated editing Group Chat database directly to update to “new” domain, but it did not succeed with the changes – so don’t even mess with that.

  • Great to know – I wouldn’t have guessed the Recent Contacts groups would be different from the other groups.


  • Curtis: Thank you for responding and updating the post. I have an explanation now for why my first test did not work. I did some more testing and changing the domain portion of the SIP address does actually work with no impact to the users. But the user’s contacts must be in a group other than the “Recent Contacts” group. So this is why it didn’t work in my first test—I had left the contacts in the default “Recent Contacts” group. Some users who don’t IM much might not create custom groups or even move any contacts out of “Recent Contacts” so this would be an issue for those users. I tested with the following:

    Office Communicator 2007 RTM client
    Office Communicator 2007 R2 client
    Lync Server 2010 CU5 (I originally tested with OCS 2007 non-R2 but then I moved the test accounts to Lync)

  • Great to know – thanks Brandon!


  • Brandon

    Changing the domain name does work. We changed this after a company name change and all we had to do was update both Exchange/OCS address books and it worked fine. We did however run into issues with changing Distribution Groups’ email address (domain name). MS says this should work, but it did not and the fixes were to update address book and have user manually remove the current DG and add the new one from address book. The other fix from server side is to use DBIMPEXP to update the email addresses that way for the DGs and the users just had to exit out and come back in and they all worked.

  • Hi,

    Yes, I only tested this with a change to the left-hand side – before the @ sign (I started the entry off with that, but I should have been more clear). I would have expected the right-hand side (domain) change to work also (assuming of course that is a supported SIP domain in the OCS deployment).

    Thanks for the info and feebback,

  • This must only work for the username part of the SIP address because I changed a user’s domain portion of the SIP address and it broke the contact. This is what I did: First I sent some test IMs between and This added John to Bob’s recent contacts in Office Communicator 2007 R2. Next I changed John’s SIP to (all the backend settings have already been configured to allow both SIP domains). Even after getting an updated address book, Bob gets an error if he tries to IM the recent contacts entry for John (this entry still references Bob can IM to John’s new SIP address fine. I tested on OCS 2007 non-R2 with MOC 2007 R2 client.

  • kottees

    thanks for this post… helped me in right time.

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