[lug] dhcp leases based on first 6 digits of mac address

David Anselmi anselmi at anselmi.us
Wed Mar 3 20:25:46 MST 2004

hugh at math.byu.edu wrote:
> I'm trying to figure out how to grant a lease to any machine based on the
> manufacturer portion of the mac address (e.g.  f0:0f:00:* should get a
> lease).  The dhcp server denies unknown clients and needs to stay that
> way.  Does anyone know how to tell the ISC dhcp server to treat f0:0f:00:*
> as known clients without having to list all 16^6 possible addresses?

It seems to be possible with version 3 of dhcpd:

match if substring (hardware, 1, 2) = 00:FF;

Not sure of the syntax, check the man page.  If this is possible with 
version 2 it is undocumented.

A complete example is at:


(grep for the above, it's a ways down).


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