DHCP Option 43 Calculator

Convert wireless controller IP addresses to DHCP Option 43 format for Cisco, Aruba, and Juniper access points.

Wireless Controller IP Address(s)

If more than one controller, separate with semicolon (;)

Vendor AP Type

📋 DHCP Option 43 Result

Type:

Length:

Value:

Option 43:

About DHCP Option 43

DHCP Option 43 is used when bringing up new Lightweight Access Points (LWAP). When the LWAP boots, it submits its DHCP request to the DHCP server. The server, when configured with Option 43, will respond with the standard DHCP response in addition to the configured DHCP Option 43 string which tells the LWAP the IP addresses of the wireless controller(s). Please reference IETF RFC 2132 for additional details.

This tool converts your wireless controller(s) IP addresses to the required format for the associated Access Points. Cisco, Aruba, and Juniper are just a few vendors that utilize DHCP Option 43 for their Access Points to learn the Wireless Controller IP Addresses.

Cisco 1000 Series: Type is 0x66, Length is the number of ASCII characters including commas, and the Value is the Wireless Controller IP Address converted to HEX.

Cisco (non-1000 Series) & Aruba: Type is 0xF1, Length is the number of access points multiplied by 4, and the Value is the Wireless Controller IP Address converted to HEX.

Juniper Trapeze: The ASCII characters are converted to their HEX counterparts. Controller Addresses are appended to "ip:" and the semicolon is replaced with a comma. Then all ASCII characters are converted to HEX values.