DHCP

[Guest]

Hi

We have a DHCP with a superscope configuration issuing IP addresses to
multiple subnets. The problem we seem to have is that when a Laptop goes from
one site to another it is issued the same IP that it had at the first site.
Obviously this won't work because of the different gateway IP's, etc.

We did try using User classes, but as we have another site with it's own
DHCP Server this didn't seem to work.

Which leads me onto 3 questions:

Can anyone shed some light on why it is doing this?
Can anyone suggest a way to stop this from happening?
If you set up a class on 2 different DHCP Servers called the same name,
would a machine using that class pick up both classes on the 2 DHCP Servers?

Thanks
Tim

 

[Phillip Windell]

Can anyone shed some light on why it is doing this?

Yes. Get rid of the Super Scope and use separate single *normal* scopes for
each subnet. SuperScopes are for MultiNets, not multiple subnets (they
aren't the same thing). MultiNets are very *rare*.

Can anyone suggest a way to stop this from happening?

Yes, Create an independent Scope for each subnet (no superscopes). You can
use one DHCP Server,...it doesn't matter which subnet it "lives" in. On the
LAN Router between the segments you will have to configure the router to
forward DHCP Queries,...this is a very common and normal proceedure for any
LAN Router that is a "real" router.

If you set up a class on 2 different DHCP Servers called the same name,
would a machine using that class pick up both classes on the 2 DHCP

Servers?

Forget the "classes",...you don't need them.

--
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
-----------------------------------------------------
Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/ISA2004_AccessRules.html

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

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

 

[Guest]

Thanks for that I will give it a go.

Can anyone shed some light on why it is doing this?

Yes. Get rid of the Super Scope and use separate single *normal* scopes for
each subnet. SuperScopes are for MultiNets, not multiple subnets (they
aren't the same thing). MultiNets are very *rare*.

Can anyone suggest a way to stop this from happening?

Yes, Create an independent Scope for each subnet (no superscopes). You can
use one DHCP Server,...it doesn't matter which subnet it "lives" in. On the
LAN Router between the segments you will have to configure the router to
forward DHCP Queries,...this is a very common and normal proceedure for any
LAN Router that is a "real" router.

If you set up a class on 2 different DHCP Servers called the same name,
would a machine using that class pick up both classes on the 2 DHCP

Servers?

Forget the "classes",...you don't need them.

--
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
-----------------------------------------------------
Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/ISA2004_AccessRules.html

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

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