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jontyplattFlag for United Kingdom of Great Britain and Northern Ireland

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Increase the size od DHCP Scope

I am using Windows 2003 as a DNS adn DHCP server. I am running out of Ip addresses. I am using 192.168.0.1  - 255 with a sub net of 255.255.255.0  I want to change the sub net to 255.255.254.0  Do i have to delete my existing scope to do this - and what about the reservations that I have already assigned - will I loose these?
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Thanks for all of this - but actually no one has answered the question. Do I have to delete my existing scope and will I have to loose all the reservations I have created?
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scadieux

Yes you need to delete the scope. As for the reservations,
You can export and import them using the netsh command.

http://koolbeans.wordpress.com/2007/07/31/howto-import-and-export-dhcp-reservations-in-server-2003/
No, you don't have to delete your existing scope because you can route the 2 subnet together with your routing unit. Therefore, what you have done will not need to be modified at all.

i hope this answer your question.
Avatar of Krzysztof Pytko
Hi,

do we speak about Windows Server DHCP ? If so, unfortunately, you have to delete scope, because Windows DHCP doesn't allow subnet mask change.

In this case the most appropriate option for you is to create another scope on DHCP server and then create "Super Scope" linking 2 or more scopes on that server to be present as one scope.

Regards,
Krzysztof
OK , we speak about Windows DHCP server :]
If you decide to change scope (change mask) then you have to recreate all reservations, because they was created for other subnet and scope.

So you can think about second variant with several subnets and routing between them
So if I have a router will I just have one DHCP server with two scopes?

Surley the easiest way of handling this is witha  superscope?
router or second network card

about superscope wait for his reply.. i do not use it before
In this instance a superscope is not an option as you still need to change the subnet mask (and therefore delete the original scope.)
A superscope is used to "group multiple scopes as a single administrative entity."
See : http://technet.microsoft.com/en-us/library/cc757614%28WS.10%29.aspx
Also:  http://technet.microsoft.com/en-us/library/cc958938.aspx

*NB* your router must allow DHCP broadcasts - you will most probably need to enable IP_Helper.
http://support.microsoft.com/kb/257579