Microsoft have announced, via the Microsoft 365 admin center Message ID MC307310 that they are removing the support of the domain for Teams Direct Routing in March 2022.

Updated January 4, 2022: We have updated the message to show for all organizations as intended. The content below has not changed. Thank you for your patience.  We're making some changes to Teams Direct Routing  On March 1, 2022, we will be removing support for and FQDNs from Direct Routing configuration.  Note: If you aren't using Session Border Controllers you can safely disregard this message.  How this will affect your organization:  When this change is implemented, if no actions taken and sip-all FQDN is used, users will no longer be able to make or receive calls via Direct Routing.  What you need to do to prepare:  Customers will need to use the recommended subnets ( and for any classification or ACL rules and discontinue using the sip-all FQDN when configuring Session Border Controls for the Direct Routing.

Why is this important? Guidance from various SBC vendors and community leaders in blog posts has always been to use this sip-all domain when configuring the SIP trunk to Microsoft Teams. Without adding the specified subnets ( & calls are likely to fail between Microsoft Teams and the SBC.

Adding the subnets on Ribbon SBC 1000/2000/SWeLite is fairly straightforward. Within the signalling group just add the IP subnets using the green cross icon into the SIP Federated IP rows section. In my example I’ve added the subnets into my previous list of all the addresses. Other SBC venders will have a similar method but you would need to refer to their documentation.

Image showing Ribbon SBC SWe Lite SIP signalling group and adding authorised Federated IP addresses

Finally, it is important to also check the firewall rules (providing there is one) between the SBCs public IP address and Teams to ensure firewall rules do not reference the address.

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