VoIP IP phone registration issues
When an IP phone is connected to a network, it goes through a registration process. When an IP phone cannot register, the following troubleshooting steps and checks should be performed.
- Make sure the voice VLAN configuration on the port of the switch to which the phone is connected is configured correctly.
- Ensure that the DHCP server is reachable on the voice VLAN and is configured correctly.
- Confirm that option 150 is configured correctly on the DHCP server and is pointing to an active TFTP server.
- Make sure the TFTP server is reachable from the voice VLAN.
Links:
https://forum.networklessons.com/t/voice-vlan/783/26?u=lagapides
https://networklessons.com/cisco/ccna-routing-switching-icnd1-100-105/voice-vlan/