Vista doesn't ack dhcp offer

Kevin Sullivan ksulliva at
Tue Sep 18 21:37:17 UTC 2007

On Sep 18, 2007, at 3:30 PM, Doug Tucker wrote:

> doesn't work for our environment.  I work at a University, where  
> all the
> new incoming student bought brand new Vista laptops, that now won't  
> work
> with our dhcp server.  We are not set up to support all these students
> and help them change their registry settings, yet, we HAVE to provide
> them network access via dhcp.  They are coming to class and cannot  
> work
> because they cannot get on.  Our dhcp server is debian, dhcp3-server

We had a similar looking problem with certain XP boxes at certain  
times.  I don't know if this is the same problem, but:

We found that XP would send DISCOVERs, which were relayed to our DHCP  
server (ISC on NetBSD) by the Cisco router.  XP wouldn't like the  
OFFERs it received from the server, so it would rebroadcast the  
DISCOVER several times.  If after three tries it didn't get an OFFER  
it liked, it would decide to take any OFFER.

However, by the time it decided to take any OFFER, it had configured  
the network interface from to 169.254.x.x.

The OFFERs as relayed by the Cisco were sent to the local network  
broadcast (x.x.x.255).  These could be received by Windows when it  
had an address of, but not when it had 169.254.x.x.  So by  
the time Windows was ready to listen to the correct answer, it could  
no longer hear the answer.

Our solution was to change the Cisco to always send relayed broadcast  
DHCP packets to, never x.x.x.255.  I don't know  
exactly how this was done, but I can found out if you'd like.  We  
have not seen this problem again since we made the change.

Hope this helps.

Kevin Sullivan
Pittsburgh Supercomputing Center

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