DHCP Option 43, part 1

Do you want to know how to configure the DHCP option 43, to allow your LWAPP / CAPWAP access points to obtain a controller IP address from the DHCP server? This may help you. I cover Windows DHCP server in this first part, and the IOS in the second part...

Category:

Education

Tags:

• cwnp
• DHCP
• option
• 43
• ccie
• wireless
• cisco
• WLC
• controller
• LWAPP
• CAPWAP

[anjaneshbabu]

Clear, concise and to the point. Vendor neutral information as well.Many thanks for putting this on line.

[cciewireless]

Glad it helped! Thanks for your kind feedback!

[towlist]

Please help me i simply dont get this. I thought this lesson was about option 43, but in the end what is configured is stated as being option "241". What happened to option 43 ? ? ?

[cciewireless]

Hi towlist,

Yes, I understand what you mean! This is a difficult point. "Option 43" is an option of the DHCP protocol that says "you are sending an option specific to a vendor device". Then, the content of that "vendor specific option" depends on what you send to which vendor. In the case of a Cisco AP, you could send many things, such as "next hop to controller", or "WLC AP Manager address" etc. From the AP standpoint, "controller Management IP address" is known as "option 241". hth!

[vejlings]

This is so good stuff. Thank you.!

[cciewireless]

Thanks vejlings!

[towlist]

Completely confused...: Aruba AccessPoints asks for option 60 in its option 55 (paramter request list) and needs the server to deliver option 60 to it to use Aruba Mobility Controller. I am completely lost (?) this does not fit with the material in this great video, indicating that option is the way a client identifies itself, not a value a client could get from a Dhcp server...Please help me to understand...

[towlist]

Completely confused...: Aruba AccessPoints asks for option 60 in its option 55 (paramter request list) and needs the server to deliver option 60 to it to use Aruba Mobility Controller. I am completely lost (?) this does not fit with the material in this gread video indicating that option is the way a client identifies itself, not a value a client could get from a Dhcp server...Please help me to understand...

[towlist]

Hi again

Inspired by your material (close to being the best on the Net i could find) i have done extensive testing. I found that more Vendor classes can exist on the same scope and hence more option 43's. That means : as long as the client can present itself with option 60 it can get it's own option43. However the "Dhcp standard" option 43 can coexist with the defined Vendor classes and clients not providing option 60 will get this "standard" option. Thank you again for your clarification.!