We have a small team who wish to use Office 365 for collaboration with partners. They only really want to use SharePoint; they're happy with their internally hosted Exchange for email, and are not looking at online Exchange. Only a handful of users in the organisation will use this online SharePoint system.

However, when we create new users in the Office 365 trial their email addresses are of the form [email protected]. We would like them to be of the form [email protected], so that if the partners try to email the users they'll have the right address.

Is this possible? We already have a domain ('example.com' in this example), but it's being used to host the company website, and we don't want to affect that.

I've read about Office 365 and Single Sign-On, but that requires ADFS (which we don't have, and expect would take too long to implement), and our team is actually happy with having to log-in to Office 365 - but they just want their email addresses to be correct.

How might we achieve this? Most of what I've read seems to be about using Exchange Online, or Signal Sign-On, and I'm a bit bewildered. Is it just a matter of adding a domain to the Office 365 plan, and then not using it?

3 Answers 3


I suggest you test with a domain not being used in production, but from what I gather, you just create the DNS records for Exchange and Lync to point to Microsoft's servers, and create the DNS records for the website to point to your web-hosting server. If your domain is through GoDaddy, there's an option to auto configure the Exchange/Lync records. We're using a domain just for the email/login purpose, so I cannot confirm that it would leave web hosting records alone.

I got my info from this surprisingly helpful "Help" link in the "Add a Domain" section of O365: http://office.microsoft.com/client/15/help/home?Shownav=true&lcid=1033&ns=O365ENTADMIN&ver=15&services=YAMMER_ENTERPRISE%2cRMS_S_ENTERPRISE%2cOFFICESUBSCRIPTION%2cMCOSTANDARD%2cSHAREPOINTWAC%2cSHAREPOINTENTERPRISE%2cEXCHANGE_S_ENTERPRISE&HelpID=O365E_DNSMgr_WhereDNSManaged1


For curiosity have you already tried as Administrator this http://onlinehelp.microsoft.com/en-us/office365-enterprises/ff637620.aspx (and step by step on the same basis available here http://www.winsupersite.com/article/office-365/office-365-custom-domain-configuration-email-142015)

  • I'd read the first of those - which still doesn't really explain to me the implications of 'adding a domain'. What does that really mean? I'll read the second link and try to understand again.
    – Andy Burns
    Jun 12, 2012 at 17:10

To add a new domain in Office365/Sharepoint Online to replace the default example.onmicrosoft.com and use it in usernames:

  1. Log in the Office 365 Admin portal (https://portal.office.com/admin) with your Admin account

  2. Click the "Domains" from the left navigation/menu bar

  3. Click the + sign (Beside "New Domain" or "Add Domain") on the top of your list of domains (You should only see the example.onmicrosoft.com by default)

  4. Click the "Start step one" and then type your domain in the field

  5. After that select your domain registrar from the drop-down list and if it isnt' there, choose the general instructions

  6. Under there you can find the DNS info you need to add (or ask your domain registrar to add them)

  7. After they've been added, you can get past that step and finish adding your domain into Office 365

  8. Finally when the domain is added, you can modify or create users and select the new domain as their username

I hope this helps! Also please let me know if I have misunderstood what you meant. :)

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