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DNS records for Skype online

Retired product. Microsoft retired Skype for Business Online on July 31, 2021, and support for Skype for Business Server 2015 and 2019 ended on October 14, 2025. Microsoft Teams replaces them. This article is kept for reference. Skype for Business Online retirement
Written July 2020. Microsoft changes these admin screens often, so the screenshots below may not match what you see today. The sequence of steps is usually still correct — if something looks wrong, tell us and we'll update it.

External DNS records required for Skype for Business Online

DNS record Purpose Value to use
SRV (Skype for Business Online) Allows your Office 365 domain to share instant messaging (IM) features with external clients by enabling SIP federation. Service:   _sipfederationtls Protocol:    _TCP Priority:    100

Weight:    1

Port:    5061

Target:   Sipfed.online.lync.com

SRV (Skype for Business Online) Used by Skype for Business to coordinate the flow of information between Lync clients. Service:   _sip Protocol:   _TLS Priority:    100

Weight:    1

Port:    443

Target:   sipdir.online.lync.com

CNAME (Skype for Business Online) Used by the Lync client to help find the Skype for Business Online service and sign in. Alias:   sip Target:   sipdir.online.lync.com
CNAME (Skype for Business Online) Used by the Lync mobile client to help find the Skype for Business Online service and sign in. Alias:   lyncdiscover Target:   webdir.online.lync.com

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