Cisco's verification for a SIP TLS trunk is a packet capture showing TCP SYN, Client Hello, server certificate exchange and then encrypted Application Data, which shows the TLS session is established.
Checked 2026-10-02
- Vendor
- Cisco
- Product
- Unified Communications Manager
- Subsystem
- SIP TLS
- Deployment
- on-premises
- Region
- not restricted
- Release range
- CUCM 9.1(2) and 10.5(2) per technote
- Checked
- 2026-10-02
Sources
- Configure SIP TLS Trunk on the Communications Manager with a CA Signed Certificate — Cisco Systems · tier 2 current vendor documentation · Verify
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting Unified CM SIP trunks that show No Service: source note cucm-sip-trunk-no-service-troubleshooting-tls-pcap-sequence. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-sip-trunk-no-service-troubleshooting-tls-pcap-sequence
BibTeX
@misc{warmtransfer-claim-cucm-sip-trunk-no-service-troubleshooting-tls-pcap-sequence,
title = {Troubleshooting Unified CM SIP trunks that show No Service: source note cucm-sip-trunk-no-service-troubleshooting-tls-pcap-sequence},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-sip-trunk-no-service-troubleshooting-tls-pcap-sequence},
note = {Source note cucm-sip-trunk-no-service-troubleshooting-tls-pcap-sequence, checked 2026-10-02}
}