How to Add the SRV Records for Office 365 to a DNS Provider

The documentation provided with Office 365 combined with the new interface make configuration of it much simpler than with BPOS. However, it isn’t without a few small bumps. I ran into one of these when I was setting up our own organization to use the Lync features. One of the requirements was to add two SRV records to our external DNS, as per the image below:

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There are actually some great guidelines and walkthroughs for setting this up with specific registrars, such as GoDaddy. However we’re using DynDNS, which is not one of the ones documented. Fair enough, I can find my way around a configuration screen, but the problem was that our DNS provider is somewhat old school. The SRV records are considered advanced (and therefore assume that I know what I’m doing with DNS), so instead of giving me nice, clearly defined fields like TTL, Port, and weight, I am presented with a single TXT field entry screen.

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This is fine if you’re a DNS expert, and know how to construct the strings, but I’m not. After a fair bit of hunting around, I was able to sort out the following syntax for adding the requisite SRV records:

Host TTL Type Data
_sip._tls.mydomain.com 60 SRV 1 100 443 sipdir.online.lync.com.
_sipfederationtls._tcp.mydomain.com 60 SRV 1 100 5061 sipfed.online.lync.com.

 

Take special note of the period at the end of the data field – this is in fact required. Once these values were added, we were off to the races with Lync – which is awesome by the way…

Your mileage may vary depending on your DNS provider, but hopefully it will help if you’re in a similar situation.

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