Subject: Re: dhcpd(8) _cannot_ be completely disabled on an interface
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Chris Jones <>
List: tech-net
Date: 01/07/2002 14:56:01
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On Mon, Jan 07, 2002 at 04:03:43PM -0500, der Mouse wrote:

> I take it you mean "source hardware _address_", ie, MAC address, here.
> > doesn't dhcpd need to know that in order to send the reply?
> > and won't it need to use a bpf in order to do so?
> Not necessarily.  It is likely enough to install an ARP entry for the
> MAC address given and the IP address assigned to that client (which can
> be done with a routing socket), and then send the packet as a normal
> UDP packet.

Sometimes, the DHCPOFFER message needs to be sent broadcast back to
the client.  In other words, the dest IP address is 0xffffffff, and
the dest MAC address is the client's.  I don't think you can do this
with UDP.

But I guess you could do it with a raw IP socket.  I've never used one
of those, though.


Chris Jones                                          Mad scientist at large

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