Source note · SIP TLS handshake failures on trunks
In Teams Direct Routing the SBC opens the TLS connection to the SIP proxy FQDN and presents its certificate; if the SIP proxy judges the request invalid it closes the TLS connection and never receives SIP OPTIONS from the SBC.
Checked 2026-09-25
- Vendor
- Microsoft
- Product
- Teams Phone Direct Routing
- Subsystem
- SIP signaling TLS
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-09-25
- Checked
- 2026-09-25
Sources
- SBC connectivity issues — Microsoft · tier 2 current vendor documentation · Overview of the SIP options process, bullets 1-2
Cite this note
APA
WarmTransfer. (2026, September 25). SIP TLS handshake failures on trunks: source note sip-tls-handshake-failures-dr-options-tls-sequence. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-tls-handshake-failures-dr-options-tls-sequence
BibTeX
@misc{warmtransfer-claim-sip-tls-handshake-failures-dr-options-tls-sequence,
title = {SIP TLS handshake failures on trunks: source note sip-tls-handshake-failures-dr-options-tls-sequence},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-tls-handshake-failures-dr-options-tls-sequence},
note = {Source note sip-tls-handshake-failures-dr-options-tls-sequence, checked 2026-09-25}
}