If the SBC never receives a SIP REFER, Microsoft advises allowing incoming connections from any Microsoft signaling IP address, because the REFER can arrive over a new TLS connection from a different address than earlier call legs.

Checked 2026-09-25

Vendor
Microsoft
Product
Microsoft Teams Phone Direct Routing
Subsystem
transfer
Deployment
multi-tenant
Region
not restricted
Release range
current as of 2026-09-25
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). Troubleshooting Teams call queues and auto attendants: source note teams-call-queue-troubleshooting-refer-any-signaling-ip. WarmTransfer. https://warmtransfer.net/knowledge/claims/teams-call-queue-troubleshooting-refer-any-signaling-ip

BibTeX

@misc{warmtransfer-claim-teams-call-queue-troubleshooting-refer-any-signaling-ip,
  title  = {Troubleshooting Teams call queues and auto attendants: source note teams-call-queue-troubleshooting-refer-any-signaling-ip},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/teams-call-queue-troubleshooting-refer-any-signaling-ip},
  note   = {Source note teams-call-queue-troubleshooting-refer-any-signaling-ip, checked 2026-09-25}
}

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