DHCPRequest for 0.0.0.0

[David W. Hankins]

On Wed, Mar 18, 2009 at 03:03:10PM +1300, Defryn, Guy wrote:
> Mar 17 16:19:55 srv-net1 dhcpd: DHCPDISCOVER from 00:0c:f1:6d:bc:c1 via 205.112.169.1
> Mar 17 16:19:56 srv-net1 dhcpd: DHCPOFFER on 205.112.169.97 to 00:0c:f1:6d:bc:c1 via 205.112.169.1
> Mar 17 16:19:56 srv-net1 dhcpd: DHCPREQUEST for 205.112.169.97 (205.112.128.32) from 00:0c:f1:6d:bc:c1 via 205.112.169.1
> Mar 17 16:19:56 srv-net1 dhcpd: DHCPACK on 205.112.169.97 to 00:0c:f1:6d:bc:c1 via 205.112.169.1

OK, that's fine.

> Mar 17 16:20:05 srv-net1 dhcpd: DHCPDISCOVER from 00:0c:f1:6d:bc:c1 via 205.112.169.1
> Mar 17 16:20:05 srv-net1 dhcpd: DHCPOFFER on 205.112.169.97 to 00:0c:f1:6d:bc:c1 via 205.112.169.1
> Mar 17 16:20:05 srv-net1 dhcpd: DHCPREQUEST for 205.112.169.97 (205.112.128.105) from 00:0c:f1:6d:bc:c1 via 205.112.169.1
> Mar 17 16:20:05 srv-net1 dhcpd: DHCPACK on 205.112.169.97 to 00:0c:f1:6d:bc:c1 via 205.112.169.1

9 seconds later it DORAs again...was the first one a bootloader (PXE)?
Or maybe an initrd?  Anyhow, seems fine, the client should be
configured now.  Again.

> Mar 17 16:20:05 srv-net1 dhcpd: DHCPREQUEST for 0.0.0.0 from 00:0c:f1:6d:bc:c1 via 205.112.169.1: unknown lease 0.0.0.0.
> Mar 17 16:20:14 srv-net1 dhcpd: DHCPREQUEST for 0.0.0.0 from 00:0c:f1:6d:bc:c1 via 205.112.169.1: unknown lease 0.0.0.0.

Whaaa?

That makes no sense at all.  Clients just shouldn't do that.  The
client is clearly broadcasting this packet, as it's being picked up by
your relay.

What could be happening here is that the client is sending a
DHCPREQUEST with no requested-address option.  In this case, piaddr(0)
would print "0.0.0.0".  This is not valid according to RFC 2131.

Can you tell us more about the client?  Maybe fire a pcap to
dhcp-bugs at isc.org?  I love pcaps.

My suspicion is that the vendor has some extended behaviour where they
do additional DHCPREQUESTs for more information (similarly to other
clients like Windows that use DHCPINFORM for this purpose shortly
after booting).

-- 
David W. Hankins	"If you don't do it right the first time,
Software Engineer		     you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins
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