Source note · Troubleshooting Cisco IP phone registration
In mixed mode phones download the CTL file from TFTP, and if the CTL contains a TFTP server entry with a self-signed certificate the phone requests a signed configuration file.
Checked 2026-09-24
If the CTL file contains a TFTP server entry that has a self-signed certificate, the phone requests a signed configuration file.
- Vendor
- Cisco
- Product
- Unified Communications Manager
- Subsystem
- CTL
- Deployment
- on-premises
- Region
- not restricted
- Release range
- Release 15 and SUs
- Checked
- 2026-09-24
Sources
- Security Guide for Cisco Unified Communications Manager, Release 15 and SUs - Security Modes — Cisco Systems · tier 2 current vendor documentation · Security Modes > endpoint behaviour in mixed mode
Cite this note
APA
WarmTransfer. (2026, September 24). Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-mixed-signed-cfg. WarmTransfer. https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-mixed-signed-cfg
BibTeX
@misc{warmtransfer-claim-cisco-phone-registration-troubleshooting-mixed-signed-cfg,
title = {Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-mixed-signed-cfg},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-mixed-signed-cfg},
note = {Source note cisco-phone-registration-troubleshooting-mixed-signed-cfg, checked 2026-09-24}
}