Source note · SIP TLS handshake failures on trunks
Because TLS 1.3 encrypts the Certificate messages, a plain packet capture of a TLS 1.3 SIP trunk cannot show whether the SBC sent its intermediates; Microsoft's capture-based check for a missing chain works directly only on TLS 1.2 sessions, and TLS 1.3 needs a key log or device-side debugs.
inferred · Checked 2026-09-25
- Vendor
- multi-vendor
- Product
- SIP trunks over TLS
- Subsystem
- packet capture analysis
- Deployment
- any
- Region
- not restricted
- Release range
- TLS 1.3 sessions
- Status
- inferred
- Checked
- 2026-09-25
Sources
- RFC 8446: The Transport Layer Security (TLS) Protocol Version 1.3 — IETF · tier 1 standards and regulators · Section 1.2, read with Microsoft 'SBC certificate or intermediary certificates are missing' section and Wireshark TLS wiki decryption section
Cite this note
APA
WarmTransfer. (2026, September 25). SIP TLS handshake failures on trunks: source note sip-tls-handshake-failures-capture-tls13-blind. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-tls-handshake-failures-capture-tls13-blind
BibTeX
@misc{warmtransfer-claim-sip-tls-handshake-failures-capture-tls13-blind,
title = {SIP TLS handshake failures on trunks: source note sip-tls-handshake-failures-capture-tls13-blind},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-tls-handshake-failures-capture-tls13-blind},
note = {Source note sip-tls-handshake-failures-capture-tls13-blind, checked 2026-09-25}
}