dhcpd MAC filter

Wayne M Barnes wayne at etaq.com
Fri Aug 20 15:47:23 PDT 2004

Dear Chuck,

   Thanks for the tip about ipfw, but I can't seem to write
an acceptable line for rc.firewall, even after reading man ipfw,
which does not show a full example.

   For instance, the following confuses ipfw when I put it
into rc.firewall:

#from man ipfw: MAC 10:20:30:40:50:60/33 any
ipfw add drop all from MAC 00:02:2d:2e:04:28 to any

    It complains that MAC is an unknown machine.

    How should I spell a firewall rule invocation that will
prevent a certain MAC serial number from getting through or to 
my FreeBSD machine?

    Thank you for any further advice.

                    -- Wayne

On Fri, Aug 20, 2004 at 02:01:26PM -0400, Chuck Swiger wrote:
> Wayne M Barnes wrote:
> >    Is there a way to allow or disallow certain computers by their
> >MAC number?
> ipfw 2 supports firewalling by MAC address, so yes.
> >    This ability comes with the software on my wireless access point,
> >but I prefer that my FreeBSD system hand out the IP addresses,
> >and I cannot find this MAC-filtering ability at man dhcpd.
> >
> >   isc-dhcp3-server-3.0.1.r14_2 is my installed port.
> >Is there another dhpcd to try?
> You can specify MAC addresses in your DHCP config to reserve specific IP 
> addresses for specific machines.  I'm not sure whether there is a way to 
> tell DHCP not to grant a lease to MAC addresses which are not found, but 
> then, without using a firewall, someone could manually configure a foreign 
> host to use the connection, regardless of whether they can get a DHCP lease.
> -- 
> -Chuck

Wayne M Barnes
wayne at etaq.com    fax: (314) 754-9556

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