[nzlug] DHCP Options

[Nick 'Zaf' Clifford]

Just to clarify, you're using a router to forward DHCP packets from
another subnet (hence the MAC address always being the same)?
Or you have some very very dumb clients that don't have mac addresses on
their ethernet interface (and therefore being totally un-compliant with
specs)?

If the former, you need to look at DHCP relay, rather than just
forwarding the packets at a layer 2 level.

If the latter, then I'm stunned that such a device exists, I've only
known such devices in development, everything's suppose to have a
"unique" mac address (I put that in quotes, as I do know some less
reputable manufacturers reuse mac addresses)

Nick


Terence Grey wrote:
> Greetings,
>
> Calling DHCP experts ...
>
> I am seeking some help with a DHCP related problem. I am running an ISC DHCP
> server with a number of dumb hosts (not pc's) that only send limited
> information in the DISCOVER packet. I am supplied with an option 61 value
> that is unique and a dummy mac address from the router. The mac address is
> always the same so I cannot use it to bind a dhcp lease. What I am looking
> for is a way to use the option 61 client-identifier to generate a unique mac
> address. One useful thing is that the client-identifier is already 12
> numeric digits long.
>
> I am already picking out the option 61 host-identifier and using to update
> the DNS like this:
>
> if exists dhcp-client-identifier {
>   ddns-hostname = substring (option dhcp-client-identifier,1,12);
> }
>
> The dhcp-options(5) man pages does not tell me what I need to know.
>
> Thank you,
> Terence
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