Problem about dhcp option 125

Glenn Satchell glenn.satchell at
Mon Mar 19 11:43:38 UTC 2012


There was a similar post recently.

Check out the dhcp-options man page in the section titled "DEFINING NEW 

The option space is for encapsulating one or more options inside another 
option. So that's something different to what you require.

You must define how the option is to encode the value, typically this is 
done in the global scope, and must be before a value is assigned.

option option-125 code 125 = string;

Then you can assign a value in various scopes as required:

option option-125 "openbsd";

The name of the option can be any string you like, as the option number 
is what is encoded in the dhcp packets.


On 03/19/12 18:26, L'oiseau de mer wrote:
> Recently i need set a dhcp sever with option 125, i use the verion 4.2.3-P2
> but i don't know how to configure.
> I also see this men page about vendor identify,
> it says that use option vivso, and later follow a string.
> So i try to these tests:
> send vivso "openbsd 5";
> send vivso 6F:70:65:6E:62:73:64:20:35;
> option vivso 6F:70:65:6E:62:73:64:20:35;
> option space openbsd code width 2 length width 2;
> option openbsd.test1-location code 1 = text;
> option openbsd.test2-probability code 2 = integer 8;
> option vsio.openbsd code 12345 = encapsulate openbsd;
> option space BSD;
> option BSD.option-125 code 125 = string;
> option BSD.option-125 "openbsd";
> But these tests is all invalid. When i see these packets in wireshark,
> i always findn't this string "openbsd".
> I don't know where is this problem, anyone can't help me?
> Thanks very much.

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