Source note · SIP TLS handshake failures on trunks
Microsoft's Direct Routing troubleshooting guidance says that if the TLS connection closes right away and no SIP OPTIONS arrive from the SBC, the TLS version may be the cause, and the SBC should be configured for TLS 1.2 or higher.
Checked 2026-09-25
The TLS version configured on the SBC should be 1.2 or higher.
- 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 · TLS connection issues, introductory paragraph
Cite this note
APA
WarmTransfer. (2026, September 25). SIP TLS handshake failures on trunks: source note sip-tls-handshake-failures-dr-closed-check-version. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-tls-handshake-failures-dr-closed-check-version
BibTeX
@misc{warmtransfer-claim-sip-tls-handshake-failures-dr-closed-check-version,
title = {SIP TLS handshake failures on trunks: source note sip-tls-handshake-failures-dr-closed-check-version},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-tls-handshake-failures-dr-closed-check-version},
note = {Source note sip-tls-handshake-failures-dr-closed-check-version, checked 2026-09-25}
}