Windows sometimes ignores DHCP offers

[Hannes]

I am writing a DHCP server. I'm having issues with both Windows 2000 Server
SP4 and Windows XPE clients sometimes ignoring my DHCP offers, where they
simply keep sending "DISCOVER" until they eventually time out and assume
169.x.x.x addresses.

Our clients do in MOST cases (95%) accept the very first offer, and
networking comes up nice and quickly. But in a few, rare cases they seem to
fail.

Restarting the DHCP Client service on failed clients always corrects the
issue.

I assume there is something slightly wrong with my DHCP OFFERs, but where
can I start troubleshooting? I can sniff the (failed) DHCP negotiation on
these clients, but who can analyze my sniff?

Thanks,

/ Hannes.

[Luke Alcatel]

Hannes,
I have some experience with XP Embedded (XPe) ignoring DHCP offers but it
may have been a special case. The XPe clients were blades with dual NICs.
During my testing I had both NICs connected to the same network and thus
they were being offered addresses by the same DHCP server. In this case XPe
frequently ignored offers, whether I used the house network DHCP server or a
local one running on a Windows box. I did a lot of sniffing but I never saw
anything wrong with the offers so I assume there was confusion in the
client. I was able to get some phone-in support from MS but they basically
blew me off by saying that having two NICs on the same machine and same
subnet was "not sensible" so they would not work to resolve the problem. I
have never seen similar problems when the NICs were being sent offers from
different DHCP servers.

As for analyzing your sniff, why not sniff when using a commercial DHCP
server and then sniff when using yours and then look for differences?

Luke

"Hannes" <hanne...@nospam.nospam> wrote in message
news:5DFF0F93-FB6F-4F17...@microsoft.com...

[Hannes]

Hi Luke,

Our offers are indeed on the same network, to different NICs - and all from
the same server. Seems to be a similar case to yours. I will try to move the
offers off to separate networks and/or utilize different DHCP servers to see
if that resolves the issue.

I early on did a lot of comparison between our DHCP offers and offers from
other servers. Apart from domain names and such, I don't see any differences
in the actual MAC/IP addresses and offers. Except for the fact that our
offers are on the same network, and come from the same server.

Legal DHCP offers getting rejected by the Windows networking stack sounds to
me like a Windows issue. Most users may not experience this, but it's legal -
and we currently do suffer from this.

Thanks for your input, I will update this post once I get a chance to try it
out!

/ Hannes.