I have Dell PowerConnect 5524.


SW01(config-dhcp)# option 43 hex f104ac1338fa


Option code 43 is not a valid HEX string.

Strange. Its worked ok for me on Cisco device. Looking at User Guide:

hex hex-string—Specifies dotted hexadecimal data: Each byte in hexadecimal character strings is two hexadecimal digits. Bytes are separated by a period or colon


SW01(config-dhcp)# option 
  ip-list              Specify an IP address list.
  POSITIVE INTEGER     Specify the DHCP option code number
SW01(config-dhcp)# option 43 
  ascii                ASCII.
  hex                  Specify Option type as Hexadecimal.
  ip                   Specify Option type as IP address.
SW01(config-dhcp)# option 43 hex 
  WORD                 Specify Option type as Hexadecimal.
SW01(config-dhcp)# option 43 hex f1.04.ac.13.38.fa
Option code 43 is not a valid HEX string.
SW01(config-dhcp)# option 43 hex f1:04:ac:13:38:fa
Option code 43 is not a valid HEX string.

Question - how do i configure option 43 on this switch?

Thanks in advance

  • Option 43 is usually used for an IP address to a WLC on a different VLAN or subnet than a WAP. Your hex string is longer than an IP address. Did you try it with an ASCII string, like option 43 ascii "" or an IP address, like option 43 ip Maybe the hex string needs to be surrounded by double-quotes "?
    – Ron Maupin
    Commented Mar 6, 2016 at 19:26
  • The fact is that cisco require strict format for their APs - first byte is F1, second is length (in my case only one address so it is 04), next four bytes is hex-digits IP address.
    – Valery
    Commented Apr 4, 2016 at 19:35
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Commented Aug 13, 2017 at 19:23

1 Answer 1


You will have difficulties towards configuring dhcp on the dell 5524 which is a layer 2 switch. A good switch in my experience, but it isn't a layer 3 switch.

You should use a layer 3 switch that provides the wanted dhcp options and/or relay the dhcp packets from your 5524 to a dedicated dhcp server (*nix dhcpd or window$ dhcp).

See this link for some more information: http://en.community.dell.com/support-forums/network-switches/f/866/t/19501905

  • Thanks. Yes, it's layer 2 switch. I called to DELL support and got info that the built-in DHCP server have a poor functionality and does not match RFC. So they propose me to use high-end models of their switches ;)
    – Valery
    Commented Apr 4, 2016 at 20:00

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