Per the CUPI SMTP client API, with IsClientSecure unchecked Unity Connection connects to the smart host on port 25 without STARTTLS, and with IsClientSecure checked it connects on port 587 using STARTTLS.
Checked 2026-10-02
Unity Connection will initiate request towards Smart Host over port 587 using STARTTLS
- Vendor
- Cisco
- Product
- Unity Connection
- Subsystem
- SMTP client TLS
- Deployment
- on-premises
- Region
- not restricted
- Release range
- 14SU2 and later
- Checked
- 2026-10-02
Sources
- Cisco Unity Connection Provisioning Interface (CUPI) API for SMTP Configuration — Cisco Systems · tier 2 current vendor documentation · SMTP client configuration > IsClientSecure field description
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting Unity Connection voicemail-to-email and notifications: source note unity-connection-notification-troubleshooting-smtp-port-tls. WarmTransfer. https://warmtransfer.net/knowledge/claims/unity-connection-notification-troubleshooting-smtp-port-tls
BibTeX
@misc{warmtransfer-claim-unity-connection-notification-troubleshooting-smtp-port-tls,
title = {Troubleshooting Unity Connection voicemail-to-email and notifications: source note unity-connection-notification-troubleshooting-smtp-port-tls},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/unity-connection-notification-troubleshooting-smtp-port-tls},
note = {Source note unity-connection-notification-troubleshooting-smtp-port-tls, checked 2026-10-02}
}