DHCP option 66 is useful for a VoIP phone to be automatically configured from a factory default state. DHCP will give the phone option 66, which points to the phone’s provisioning server. The phone can then contact the server to download its configuration or upgrade its firmware.

ASUSWRT-Merlin is an open-source fork of ASUSWRT stock firmware.



First, these options must be enabled from the Web GUI

Administration > System > Enable JFFS partition > Yes
Administration > System > Format JFFS partition at next boot > No
Administration > System > Enable SSH > Yes


Next, SSH into the router and open the jffs/configs directory

cd /jffs/configs

Create/edit dnsmasq.conf.add with vi text editor

vi dnsmasq.conf.add

Enter your DHCP Option 66 into dnsmasq.conf


Save that (ESC, :wq, ENTER), then reload dnsmasq

service restart_dnsmasq

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