Source note · Troubleshooting Cisco IP phone registration
Cisco TAC states the ITL file needs deleting from a phone only when all of these hold: the phone's ITL signature does not match the TFTP server's ITL, the TVS signature in the ITL does not match the certificate presented, the phone shows verification failures, and no backup of the old TFTP private key exists.
Checked 2026-09-24
- Vendor
- Cisco
- Product
- Unified Communications Manager
- Subsystem
- ITL
- Deployment
- on-premises
- Region
- not restricted
- Release range
- CUCM 8.0 and later
- Checked
- 2026-09-24
Sources
- Understand CUCM Security By Default and ITL Operation and Troubleshooting — Cisco Systems · tier 2 current vendor documentation · Understand CUCM Security By Default and ITL Operation and Troubleshooting > when the ITL file must be deleted
Cite this note
APA
WarmTransfer. (2026, September 24). Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-itl-delete-cond. WarmTransfer. https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-itl-delete-cond
BibTeX
@misc{warmtransfer-claim-cisco-phone-registration-troubleshooting-itl-delete-cond,
title = {Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-itl-delete-cond},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-itl-delete-cond},
note = {Source note cisco-phone-registration-troubleshooting-itl-delete-cond, checked 2026-09-24}
}