Dhcpd versus Windows Vista

A.J. Werkman AJ.Werkman at digifarma.nl
Wed Mar 14 08:58:43 UTC 2007

At 18:00 12-03-2007, you wrote:
>I don't think your problem and the knowledge base entry are related.
>The KB article describes a problem where either the DHCP server or 
>something in
>the network between the client and the server (like a router or a switch) 
>the DHCP packet from the client because the broadcast flag is set in Vista.
>However, since the server is actually issuing a lease to the client, this is
>probably not it.
>You point out that everything works when you open the firewall. Badly 
>firewalls are often a source of problems for DHCP. My recommendation would 
>be to
>use Google, and try to find another user with a similar setup and a solution.
>Failing that, most firewalls have some documentation of some kind. ;)

I think I have to redescribe this a bit.

What I call Firewall is actually a linux machine with dual nic. On one side 
I have a public IP subnet on the other side I have a private IP subnet in 
the 172.16.x.x range. On this machine I have port forwarding turned off. 
Furthermore I have a complete ACCEPT entry in the iptables list for the 
private-side NIC. So this should not interfere with DHCP packets.

Btw this machine is also doing the DHCP. I don't have any other DHCP 
"source" on the subnet. If I use linux or XP on the client hardware there 
is no problem with the DHCP. The machine accepts a lease just as expected. 
Only a vista installation does not accept the lease. Only if I configure 
NAT on the linux machine, Vista starts to accept DHCP leases. Also if I 
replug this client to the public side of the network, where the same isc 
DHCP-server on the linux machine hands of public IP-addresses I do not see 
any DHCP problems.

I also used different hardware for the client to verify. And I do reproduce 
the same behaviour as describe above. In my opinion this rules out hardware 
problems. So at the moment, the only thing I can think of, is that Vista 
itself acts strange if it can not reache mother Microsoft directly 
(although this should be irrelevant in the DHCP process) or it is the 
combination Vista/DHCP server that produces the problem. At the moment I am 
out of ideas, how to debug this problem further.

I already have searched the internet, but can't find reports of problems, 
that look the same.

On some Vista groups I have put this question, that I also want to place 
here. Are there people around, that can easily put up a little test lab of 
linux server and vista client and try to reproduce this problem. Without 
confimation that this problem is reproducable, I start to think this 
problem is related to my personal magnetism or some other goastly source ;-).


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