DHCP & multple subnets/scopes

[HacksNTweaks]

OK, here's the scenario:

W2K server running DHCP server and dynamic DNS (no WINS). There are 4 scopes within a superscope set up as follows:
10.2.x.x/16 (10.2.1.1 - 10.2.2.254)
10.3.x.x/16 (10.3.1.1 - 10.3.2.254)
10.4.x.x/16 (you get the idea!)
10.5.x.x/16 ("" "&quot
The subnets are "routed" using a Cisco layer 3 switch using IP helper address on each appropriate interface.

The clients are either W2K or XP. They pick up appropriate IP configuration information on their respective subnets and all is fine and dandy. Pretty straight forward stuff, but...

The problem:
A good number of users (laptops) must move between subnets. What's happening is that they retain their previous dynamic IP information. I've tried having them do a release before shutdown to no avail. The only thing that works is to delete the DHCP lease entry for that IP address in the scope. Then, they can pick up an address for the correct subnet. This has also happened with a DHCP configured Intel print server (don't ask the obvious question here. It has to do with the previous admin!).

Is there some setting I'm missing here, folks!?

Any help is truly appreciated!

HacksNTweaks

 

[Drakujii]

Is your DHCP server IP address is within one of these scope??? If not, try creating a scope on the same IP subnet as the DCHP server's.

 

[dbMark]

DHCP leases by default to expire after 15 minutes as I recall, you could lower that to a shorter time period, such as 3 to 5 minutes. Not too short, or your network will have a lot of traffic just renewing those leases all the time. Anyway, how fast do they walk from one office to another?

 

[HacksNTweaks]

Thanks, Drakujii.

The servers all reside on the 10.2 subnet and are statically IP'd within the predefined static range (as are the print servers now!). Could this have something to do with DNS not dynamically updating correctly? DHCP is set up to automagically update DNS.

Additional note: This is a single domain environment, for whatever that's worth, and the subnets are on separate VLAN's.

There are 10 types of people in the world. Those who understand binary, and those who don't.

 

[HacksNTweaks]

Hi, dbMark. Thanks for your input.

Actually, the default lease expiration is eight days on w2k DHCP servers (up from three on nt4). I thought about that option (lowering the exp. time). I think that's putting too many DHCPrequests on the network though for something that should have a more straight forward answer. It just seems I'm overlooking something that's staring me straight in the face!


HacksNTweaks

There are 10 types of people in the world. Those who understand binary, and those who don't.