On Cisco IP Phone 8800 series, TFTP authorization fails when the phone's TFTP address is not in the CTL file, for example after a new CTL adds a TFTP server the phone's existing CTL lacks.
Checked 2026-10-01
- Vendor
- Cisco
- Product
- IP Phone 8800 Series
- Subsystem
- Phone security
- Deployment
- on-premises
- Region
- not restricted
- Release range
- current as of 2026-10-01
- Checked
- 2026-10-01
Sources
- Cisco IP Phone 8800 Series Administration Guide for Cisco Unified Communications Manager - Troubleshooting — Cisco Systems · tier 2 current vendor documentation · Cisco IP Phone Security Problems > CTL File Problems > TFTP Authorization Fails
Cite this note
APA
WarmTransfer. (2026, October 1). Troubleshooting phone trust and ITL failures in Unified CM: source note cucm-itl-trust-troubleshooting-p8800-tftp-not-in-ctl. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-itl-trust-troubleshooting-p8800-tftp-not-in-ctl
BibTeX
@misc{warmtransfer-claim-cucm-itl-trust-troubleshooting-p8800-tftp-not-in-ctl,
title = {Troubleshooting phone trust and ITL failures in Unified CM: source note cucm-itl-trust-troubleshooting-p8800-tftp-not-in-ctl},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-itl-trust-troubleshooting-p8800-tftp-not-in-ctl},
note = {Source note cucm-itl-trust-troubleshooting-p8800-tftp-not-in-ctl, checked 2026-10-01}
}