cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
136
Views
0
Helpful
1
Replies
Highlighted
Beginner

DHCP Option 43

Is there a maximum length for DHCP option 43 in Cisco IOS?

 

Everyone's tags (2)
1 REPLY 1
Rising star

Re: DHCP Option 43

Hello

Windows DHCP server

"Complete these steps in order to define DHCP Option 43 on the Windows DHCP server:
1. In the DHCP Server scope, right-click Server Options and choose Configure Options.
2. On the General tab, scroll to Option 43 and check the 043 Vendor Specific Info check box.
Enter the Option 43 sub-option in hex.Note: TLV values for the Option 43 suboption: Type +
Length + Value. Type is always the suboption code 0xf1. Length is the number of controller
management IP addresses times 4 in hex. Value is the IP address of the controller listed
sequentially in hex. For example, suppose there are two controllers with management
interface IP addresses, 192.168.10.5 and 192.168.10.20. The type is 0xf1. The length is 2 * 4
= 8 = 0x08. The IP addresses translates to c0a80a05 (192.168.10.5) and c0a80a14
(192.168.10.20). When the string is assembled, it yields f108c0a80a05c0a80a14. The Cisco
IOS command that is added to the DHCP scope is option 43 hex f108c0a80a05c0a80a14.
3.
Click Apply and then click OK.Once you complete this step, the DHCP Option 43 is
configured and the DHCP server sends the option 43 to the LAPs."

 

Cisco IOS CLI.
The hexadecimal string in step 3 is assembled as a sequence of the TLV values for the
Option 43 suboption: Type + Length + Value. Type is always the suboption code 0xf1.
Length is the number of controller management IP addresses times 4 in hex. Value is the IP
address of the controller listed sequentially in hex.For example, suppose there are two
controllers with management interface IP addresses, 192.168.10.5 and 192.168.10.20. The
type is 0xf1. The length is 2 * 4 = 8 = 0x08. The IP addresses translate to c0a80a05
(192.168.10.5) and c0a80a14 (192.168.10.20). When the string is assembled, it yields
f108c0a80a05c0a80a14. The Cisco IOS command that is added to the DHCP scope is:

 

The value is the same for Cisco IOS and Windows

 

Check it for more information: https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/97066-dhcp-option-43-00.pdf

Jaderson Pessoa
*** Rate All Helpful Responses ***
CreatePlease to create content
Content for Community-Ad
August's Community Spotlight Awards