How to restrict Windows XP DHCP clients to a specific subnet?

Glenn Satchell glenn.satchell at
Fri Feb 14 01:51:27 UTC 2014

On Fri, February 14, 2014 12:59 am, Simon Hobson wrote:
> Ole Holm Nielsen <Ole.H.Nielsen at> wrote:
>> Cool!  I like this, but where is the documentation of this?  Googling it
>> didn't seem to give any hits...
> It isn't really documented, it's one of those tricks that uses a function
> (or a side effect of it) for a different purpose to what it was provided
> for.
> Basically, you can set a variable to be used elsewhere, and I assume this
> is probably documented (not used it myself, so never looked). A side
> effect of setting a variable is that it's stored in the leases file -
> hence if you want to put some information in the leases file (eg for
> debugging what classes have been matched) then setting a variable (which
> you never actually reference) will do it.

It's in the dhcpd.leases(5) man page:

     set variable = value;

     The set statement sets the value of a variable on the lease.
     For  general  information on variables, see the dhcp-eval(5)
     manual page.


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