If an 8800 phone reaches the TFTP server or Cisco Unified CM by DNS name, a DNS server must be specified. Cisco's DNS check also says to confirm a CNAME entry exists for the TFTP server and the Unified CM system, and that reverse lookups are configured.
Checked 2026-10-02
- Vendor
- Cisco
- Product
- Cisco IP Phone 8800 Series
- Subsystem
- DNS
- Deployment
- on-premises
- Region
- not restricted
- Release range
- current as of 2026-10-02
- Checked
- 2026-10-02
Sources
- Cisco IP Phone 8800 Series Administration Guide for Cisco Unified Communications Manager - Troubleshooting — Cisco Systems · tier 2 current vendor documentation · Phone Displays Error Messages > Phone Cannot Connect Using DNS; Troubleshooting Procedures > Verify DNS Settings
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting IP phones that do not get a voice VLAN or DHCP options: source note ip-phone-dhcp-vlan-troubleshooting-dns-name-needs-dns-server. WarmTransfer. https://warmtransfer.net/knowledge/claims/ip-phone-dhcp-vlan-troubleshooting-dns-name-needs-dns-server
BibTeX
@misc{warmtransfer-claim-ip-phone-dhcp-vlan-troubleshooting-dns-name-needs-dns-server,
title = {Troubleshooting IP phones that do not get a voice VLAN or DHCP options: source note ip-phone-dhcp-vlan-troubleshooting-dns-name-needs-dns-server},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/ip-phone-dhcp-vlan-troubleshooting-dns-name-needs-dns-server},
note = {Source note ip-phone-dhcp-vlan-troubleshooting-dns-name-needs-dns-server, checked 2026-10-02}
}