DHCP assigning wrong addresses on vlan with correct gateway addres

Hi all, I am having an issue with DHCP on 2 Windows 2003 Enterprise servers
running SP1. First let me detail the network layout. I have a layer2/3 switch
on which i have configured 3 vlans. The switch performs the routing for these
vlans and is the default gateway for them all. For example

Vlan1 - 192.168.1.1
Vlan2 - 192.168.2.1
Vlan3 - 192.168.3.1

I have 2 DHCP servers which are configured with superscopes for the subnets
addresses relating to the vlan configured. For example lets say
192.168.1.1-254, 192.168.2.1-254 & 192.168.3.1-254. The 2 servers are located
on Vlan1 and i have configured DHCP relaying for the Vlans on the switch to
the server addresses in Vlan1. The servers Default Gateway is the vlan1
address.

When i plug in a PC to a Vlan i get the correct address for that vlan. The
address is registered with the DHCP servers and all works fine. However when
i then try and move the PC into a different vlan by unplugging it and
physically moving it, the DHCP server responds with the old address even
though the PC is now in the new Vlan.

I have sniffed the network with Ethereal and i can see the client is
requesting the IP address it used to have in the old vlan and even though the
DHCP server can see it came from a different Vlan gateway it supplies the old
address back to the client. So i end up with a wrongly addressed client in
the new vlan.

When i issue the ipconfig/release command before physically moving the PC
into the new vlan i do get the correct address for the new vlan issued to the
client.

The twist is though i have 2 supposedly exactly the same conifgs on the DHCP
servers in 2 different sites. (The only difference is in the subnets they are
supplying addresses for). The switches are config exactly the same as well.
Site 1 allows a client PC to swap Vlans and always supplies the correct
address for the vlan to the Client whereas Site 2 works as detailed above.
The server option of DHCP release lease on shutdown is not configured on
either site as this will impact on other equipment i have.

Any help will be greatly appreciated.


havin.issues

"havin.issues" <(E-Mail Removed)> wrote in message
news:ABDB4D04-39C3-40D2-8593-(E-Mail Removed)...
> Hi all, I am having an issue with DHCP on 2 Windows 2003 Enterprise
> servers
> running SP1. First let me detail the network layout. I have a layer2/3
> switch
> on which i have configured 3 vlans. The switch performs the routing for
> these
> vlans and is the default gateway for them all. For example
>
> Vlan1 - 192.168.1.1
> Vlan2 - 192.168.2.1
> Vlan3 - 192.168.3.1
>
> I have 2 DHCP servers which are configured with superscopes for the
> subnets
> addresses relating to the vlan configured. For example lets say

Get rid of the Superscopes. That is *not* what Superscopes are for.
Use normal, separate, distinct, independent Scopes for each subnet.

Superscopes are for Muti-Netting where multiple Scopes all behave as a
single Scope (the opposite of what you want). A client can be given any
address at any time from any scope inside the superscope. In a Multi-Net
multiple IP segments operate on the same "wire" as behave collectively as
the same subnet. VLANs also operate on the same "wire" but are *separated*
by the Frame Tagging, which does not exist in a Multi-Net. Since VLANs
were invented, the Multi-Net has almost no reason to ever exist,...along
with their accompanying Superscopes.

--
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
-----------------------------------------------------
Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/IS...cessRules.html

Troubleshooting Client Authentication on Access Rules in ISA Server 2004
http://download.microsoft.com/downlo...7/ts_rules.doc

Microsoft Internet Security & Acceleration Server: Guidance
http://www.microsoft.com/isaserver/t...dance/2004.asp
http://www.microsoft.com/isaserver/t...dance/2000.asp

Microsoft Internet Security & Acceleration Server: Partners
http://www.microsoft.com/isaserver/partners/default.asp

Deployment Guidelines for ISA Server 2004 Enterprise Edition
http://www.microsoft.com/technet/pro...isaserver.mspx
-----------------------------------------------------