Microsoft Teams and DNS

Those entering the world of Microsoft UC solutions with Teams are not familiar with the following DNS entries. Those coming to Microsoft Teams from Lync or Skype for Business Server know them very well.

TypeValue
SRVService: sipfederationtls
Protocol: TCP
Priority: 100
Weight: 1
Port: 5061
Target: sipfed.online.lync.com
SRVService: sip
Protocol: TLS
Priority: 100
Weight: 1
Port: 443
Target: sipdir.online.lync.com
CNAMEAlias: sip
Target: sipdir.online.lync.com
CNAMEAlias: lyncdiscover
Target: webdir.online.lync.com

Am I interested in these entries as a TEAMS administrator? Absolutely!

  1. Missing DNS records can accidently prevent appreciated business relationships through Interop Federation between Microsoft Teams and Skype for Business.
  2. One or another Contact Center solution for Microsoft Teams still relies on Interop Federation between Microsoft Teams and Skype for Business for some features.
  3. Incorrect values can cause me headaches when integrating new domains into my tenant.

If I want to chat with a business partner still on Skype for Business Server, his Server infrastructure uses the SRV record sipfederationtls to my domain to find me as a Federated Partner. Target for this SRV record is the Skype for Business Online Access Edge Server sipfed.online.lync.com.

If my company only uses Microsoft Teams, the other entries are not relevant to me. Aren’t they?

Today Microsoft recommends ALL entries, and for good reason: For example in case of a company acquisition, where the information about an infrastructure and its history is incomplete, the Teams administrator can get lost when troubleshooting: Outdated DNS entries for decommissioned Lync or Skype for Business Servers always impact Teams services and Federation.

Published by Natalie Jeschner

Natalie quit her profession as a social worker 2000 and started her IT career as a support employee. She sticked to error analysis and troubleshooting in enterprise infrastructures for 15 years and discovered her passion for Collaboration, Unified Communication and VoIP during that time. Her focus is on the design and implementation of VoIP infrastructures with Microsoft UC solutions for several years now.
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