Polycom VVX 410 phones connected to the your primary network do not receive IPs via DCHP from the Bluecat DHCP server and cannot register with 8x8.
Phones connected to a Sophos UTM (connected to your primary network) are able to receive IP addresses handed out by the Sophos box.
Polycom phones, Bluecat DHCP
Disable CDP and LLDP
Disabling CDP and LLDP on the Polycom phones removed the restriction. The phones were able to receive offers from the DHCP server and were able to register and be activated with 8x8.
To disable CDP and LLDP
- On the phone's Web GUI, go to Settings > Network > Ethernet.
- Under VLAN Settings, check Disable for LLDP and CDP.
- Save all changes.
- Allow the phone to reboot.
Polycom phone settings are blocking the return messages with IP addresses from the Bluecat DHCP server.