[rhelv6-list] dhcpd question: limiting scope to mac address identifiers

[Greg Swift]

On Thu, Dec 27, 2012 at 7:41 PM, solarflow99 <solarflow99 at gmail.com> wrote:

> I have been testing with a second dhcp server on the same vlan, and
> wanted to limit the scope to only serve out to clients that have mac
> addresses that start with the same 3 octets, something like this
> maybe?
>
>
> class "custom-clients" {
>          match if substring (option dhcp-client-identifier, 00:50:56);
>        }
>
> deny unknown-clients;
>
>
you are very close.  if you search for 'isc dhcp match vendor' you should
get a lot of helpful information.  You can simply use the hardware address
rather than an option.  Plus unknown-clients refers to systems that do not
have a host entry in your file.  In this case none do, so all clients would
be denied.  You can either do an allow block:

or

class "good" {
 match if substring(hardware,1,3) = AA:BB:CC;
}

allow members of "good";


or a deny block


class "bad" {
 match if not substring(hardware,1,3) = AA:BB:CC;
}

deny members of "bad";



In an ideal world they work the same, but test it out and see how they
do for your use case.

-greg
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