Assigning a Fixed IP Address Based on dhcp-client-identifier

Scott Coleman swarga.research at
Tue May 19 21:44:22 UTC 2009

On Tue, May 19, 2009 at 1:12 PM, Glen R. J. Neff <neff_glen at> wrote:
> On Tue, 2009-05-19 at 11:41 -0700, Scott Coleman wrote:
> > >    This is kind of counter-intuitive, and I've fought with this
> > before, but
> > >    static assignments need to be outside your scope.
> >
> > Glen,
> >
> > I'm not sure what you mean here. The hosts are already declared at the
> > outermost scope.
> But the static IPs you're trying to assign are inside the scope you've
> defined.  A scope is a pool of IPs for dynamic assignment.
> Adjust your scope to not include the IPs you're trying to statically
> assign, or switch your static assignments to IPs outside of the scope.

OK, I changed the range so as not to conflict with the fixed
addresses. Still "no free leases."


I also tried putting in the uid statements suggested elsewhere:

host pos_30
  option dhcp-client-identifier "\0pos_30";
  option host-name "pos_30";
  uid 00:70:6f:73:5f:33:30;

The byte list is an exact match for the 7 bytes the client is sending
in the DHCPDISCOVER packet, but dhcpd -t reports

mdb.c(319): non-null pointer

and the server still reports "no free leases."

> I've always just used MAC address for static assignments, but I've
> encountered that very issue.

Normally I use the MAC address and be done with it, but in this case I
have an externally-imposed requirement to use the client-id only.

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