AP Discovery - How to configure DHCP option 43 to discover the controller?

[Orlando_Elias]

The DHCP option 43 is one of many methods for the RUCKUS AP to discover its controller.

This option is configured in the DHCP server and must be masked. Also, the vendor code and the length of the IP address must be specified in HEX.

RUCKUS vendor code:

- 06 for SmartZone

- 03 for Zone Director

Using this website you will quickly mask the IP address from IPV4 to dnsmasq values.  

For example, let's mask the IP address 192.168.0.200 using the website: the final value to enter in your DHCP server is "060d3139322e3136382e302e323030"

How did they get to such a result? 

1. Divide the IP Address: Start by splitting the IP address into its four individual parts: A.B.C.D.

   1. 192
   2. 168
   3. 0
   4. 200

2. Mask the decimal values: For each part, convert the decimal value to its corresponding hexadecimal representation. For instance:

   • Decimal 1 becomes "31"
   • Decimal 9 becomes "39"
   • Decimal 2 becomes "32" ...

3. Add Separators: Place "2e" (ASCII value for dot) between each pair of translated hex values.

4. Include Vendor Code and Length: Prefix the vendor code at the beginning (e.g., "06" for RUCKUS). Add the IP address length in bytes (e.g., "0d" for 13 bytes).

   Note: The length is 13 bytes since each pair of characters equals one byte.

5. IP Address Translation: The IP address "192.168.0.200" transforms into the hexadecimal string "3139322e3136382e302e323030".

6. Combining Elements: Combine all the translated parts to form the final hexadecimal representation.

Example for the IP address "192.168.0.200":

• Translated octets: "31", "39", "32", "2e", "31", "36", "38", "2e", "30", "2e", "32", "30", "30"
• Vendor code: "06"
• Length: "0d"
• Combined: "060d3139322e3136382e302e323030"

Visit this post to learn other ways to provision RUCKUS APs with the IP address of their controllers.