Source note · Cisco IP phone registration and TFTP and ITL and CTL
Cisco warns never to regenerate the CallManager.pem and TVS.pem certificates at the same time; after changing either, TFTP and TVS services are restarted and phones reset to pick up the new ITL.
Checked 2026-09-24
Never regenerate both the CallManager.pem and TVS.pem certificates at the same time.
- Vendor
- Cisco
- Product
- Cisco Unified Communications Manager
- Subsystem
- Certificates
- Deployment
- on-premises
- Region
- not restricted
- Release range
- as of technote update 2023-07-14
- Checked
- 2026-09-24
Sources
- Understand CUCM Security By Default and ITL Operation and Troubleshooting — Cisco Systems · tier 2 current vendor documentation · Regenerate Certificates section
Cite this note
APA
WarmTransfer. (2026, September 24). Cisco IP phone registration and TFTP and ITL and CTL: source note cisco-phone-registration-no-dual-cert-regen. WarmTransfer. https://warmtransfer.net/knowledge/claims/cisco-phone-registration-no-dual-cert-regen
BibTeX
@misc{warmtransfer-claim-cisco-phone-registration-no-dual-cert-regen,
title = {Cisco IP phone registration and TFTP and ITL and CTL: source note cisco-phone-registration-no-dual-cert-regen},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cisco-phone-registration-no-dual-cert-regen},
note = {Source note cisco-phone-registration-no-dual-cert-regen, checked 2026-09-24}
}