In the Direct Routing SIP OPTIONS process, the SBC first opens a TLS connection to the SIP proxy FQDN (for example sip.pstnhub.microsoft.com). If the SIP proxy judges the connection request invalid, it closes the TLS connection and never receives OPTIONS from the SBC.

Checked 2026-09-25

Vendor
Microsoft
Product
Microsoft Teams Phone Direct Routing
Subsystem
sip-options
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 Direct Routing: source note teams-direct-routing-troubleshooting-options-tls-first. WarmTransfer. https://warmtransfer.net/knowledge/claims/teams-direct-routing-troubleshooting-options-tls-first

BibTeX

@misc{warmtransfer-claim-teams-direct-routing-troubleshooting-options-tls-first,
  title  = {Troubleshooting Teams Direct Routing: source note teams-direct-routing-troubleshooting-options-tls-first},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/teams-direct-routing-troubleshooting-options-tls-first},
  note   = {Source note teams-direct-routing-troubleshooting-options-tls-first, checked 2026-09-25}
}

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