A few weeks ago, I wrote about configuring DNS for Exchange Online in Office 365. In that post, I mentioned that Microsoft is only supporting small business customers with domains that are delegated to (i.e. hosted on) Microsoft’s name servers – currently ns1.bdm.microsoftonline.com and ns2.bdm.microsoftonline.com.
I wasn’t entirely comfortable with this (for a start, the Office 365 DNS Manager is best described as “basic”), so I decided to see what happens if I went through the process, but never actually switched over the name server records… as it happens it seems to work quite well (albeit in an unsupported manner).
If you want to retain control of settings, all that’s involved is creating the same records with an external DNS provider.
For reference, on the markwilson.co.uk domain, these would be:
autodiscover 3600 IN CNAME autodiscover.outlook.com.
markwilson.co.uk. 3600 IN TXT “v=spf1 include:outlook.com ~all”
SRV _sip _tls 443 1 100 sipdir.online.lync.com. markwilson.co.uk 3600
SRV _sipfederationtls _tcp 5061 1 100 sipfed.online.lync.com. markwilson.co.uk 3600
Of course, if Microsoft changes the server names, you won’t be notified and that might affect your service but the settings seem to be the same as the ones provided to Enterprise customers as part of their domain management process.
Then, go through the normal process to add a domain to Office 365, but just click Next on the Edit Name Server Records page:
At the time of writing, Office 365 is still in beta, so things could change (for example, the domain verification process has already switched from using CNAME records to using either TXT or MX records) but it might be worth a try…
[Update 20 June 2011: Microsoft has documented a workaround for domains that do not allow delegation (specifically for .NO and .DK but I see no reason why other domains should not be used in this way)]