Vista Wireless DHCP Problem

[NeilOrangePeel]

Hi all

Got another Vista wireless networking problem.

Running Vista Business and connecting to a 3Com Officeconnect wireless router - this is set as a DHCP server with a pool of 5 addresses - MAC address filtering and WEP are enabled.
We also have another DHCP server on the same subnet (not a great idea I know but the boss's decision unfortunately)

When I connect to the 3Com, although it connects successfully, it uses the other DHCP server to assign a valid IP but doesn't assign DNS settings. Both can assign these ok, tested with XP.

I would have thought that this was the other DHCP answering before the router if it assigned the full details but it doesn't assign the DNS or gateway.
I tried using the TIDs from MS to adjust the broadcast flag to see if it was an issue with the type of router but makes no difference. Have also tried other KB articles and changed the values for the DHCP in the registry (changes back to the incorrect one once connected)

Things I've tried with no success:

Recreate the connection
Manually assigning an IP etc works ok
Disabled MAC filtering and encryption - same results.
Disabled IPv6
Changed Broadcast flag
Manually edited details in registry
Release/renew/flush ipconfig
Searched here and other places for solutions and tried most....

One more bizarre thing that happened is that this same problem was affecting 2 laptops running Vista - one of them picked up valid info from the 3Com and has stuck with it - even after the lease would have expired.....can't explain what happened for it to connect (other DHCP didn't reply in time?)

+-------------+     +-------+     +----------+
|Vista Laptop |---->|Router | --->|Other DHCP|
+-------------+     +-------+     +----------+

* Any ideas why the 3Com won't dish out IP/GW/DNS etc?
* Why the replying DHCP only gives out IP?
* How to fix it?

Any help appreciated

 

[smah]

The only reliable way to 'fix' the problem is to only have 1 dhcp server. Beyond the fact that it's the boss's decision, may I inquire why he/she thinks there's a need to do this and/or why they need to be the same subnet? There is no way to guarantee that the wireless clients will get their address from the wireless router under these conditions.

 

[linney]

Anything of interest in these? I don't know the answer, but it may be tactful to allow you boss to solve the problem (or at least think that he has).

Automatic Configuration for Multiple Networks

http://windowshelp.microsoft.com/Windows/en-US/Help/deafc97a-6ff4-4f57-b3a4-fab84388ef1f1033.mspx

HOW TO: Use the Alternate Configuration Feature for Multiple Network Connectivity (Q283676)

http://support.microsoft.com/default.aspx?scid=kb;EN-US;q283676

 

[NeilOrangePeel]

Thanks for the replies - although I agree that 1 DHCP server is the way ahead I believe this is a Vista issue. It connects through the router we want DHCP from to reach the one that it does use - XP etc all work fine as the router responds quickest (as you'd expect)
Have applied MS fixes for DHCP broadcast flag and ARP, also various other fixes found from people with the same issues!
Seems to be widely affecting people - wireless not picking up DHCP and setting itself to 'Local Access Only'

Anyone managed to fix this yet?