Ubiquiti UniFi DHCP Option 43 for Automatic Controller Discovery
To ensure all AP’s on a network connect to the controller automatically you have to configure an additional option in the DHCP Server of the LAN where the UniFi devices are being connected to.
Add option 43 as a string with the IP address in HEX notation after appending the HEX result with 01:04. Example:
– If IP address of controller is 126.96.36.199.
– The hex representation of 188.8.131.52 is 0x:01:02:03:04. An online IP address to hex converter can be found at https://www.miniwebtool.com/ip-address-to-hex-converter/?ip=184.108.40.206.
– Add 01:04 to the beginning of the hex so it ends up similar to 01:04:0x:01:02:03:04.
– Create an option in DHCP with number 43, make the value “string”, and then enter the completed hex value as 01:04:0x:01:02:03:04 (or whatever the value is for your IP).