Yealink IP Phones Auto Provisioning Guide 
34 
DHCP Options 
Yealink IP phones can obtain the provisioning server address by detecting DHCP options during 
startup. 
If you are using IPv4 network, the phone will automatically detect the option 66 and option 43 
for obtaining the provisioning server address. DHCP option 66 is used to identify the TFTP server. 
DHCP option 43 is a vendor-specific option, which is used to transfer the vendor-specific 
information. 
If you are using IPv6 network, the phone will automatically detect the option 59 for obtaining 
the provisioning server address. DHCP option 59 is used to specify a URL for the boot file to be 
downloaded by the client. 
You can configure the phone to obtain the provisioning server address via a custom DHCP 
option. You can select to use IPv4 or IPv6 custom DHCP option according to your network 
environment. To obtain the provisioning server address via an IPv4 or IPv6 custom DHCP option, 
make sure the DHCP option is properly configured on the phone. The IPv4 or IPv6 custom DHCP 
option must be in accordance with the one defined in the DHCP server. 
To configure the DHCP option via web user interface: 
1.  Click on Settings->Auto Provision. 
2.  Mark the On radio box in the DHCP Active field. 
3.  If you are using IPv4 network, enter the desired value in the IPv4 Custom Option field. 
4.  If you are using IPv6 network, enter the desired value in the IPv6 Custom Option field. 
 
5.  Click Confirm to accept the change. 
During startup, the phone will broadcast DHCP request with DHCP options for obtaining the 
provisioning server address. The provisioning server address will be found in the received DHCP 
response message. 
After the IP phone obtains the provisioning server address from the DHCP server, it will connect 
to the provisioning server and perform auto provisioning during startup. 
For more information on the DHCP options, refer to
 
the latest Administrator Guide for your 
phone on Yealink Technical Support.