Resubnetting DHCP server scope

Pertaining to Windows 2003 Server Standard Edition, is there any way
to change the subnet on a DHCP scope without first removing the
existing scope? I need to go from a 24 bit subnet mask to a 22 bit
subnet mask. If I have to remove the existing scope, how am I going
to keep the clients from requesting addresses already in use that were
handed out previously by the deleted scope? Thanks.

PS: There is a MS KB article on this however it does not go into any
detail. The article is at http://support.microsoft.com/?kbid=255999

Matt

(E-Mail Removed) (Matt) wrote in message news:<(E-Mail Removed). com>...
> Pertaining to Windows 2003 Server Standard Edition, is there any way
> to change the subnet on a DHCP scope without first removing the
> existing scope?

Not that I am aware. However, you can keep your existing scope a while.
Set the new scope up on a second DHCP server and do the conversion
in parallel. Once complete, retire DHCP on the original server.

> I need to go from a 24 bit subnet mask to a 22 bit
> subnet mask. If I have to remove the existing scope, how am I going
> to keep the clients from requesting addresses already in use that were
> handed out previously by the deleted scope? Thanks.

You can set up exclusions for the range of addesses that are already
leased. You may remove that exclusion once all those leases have
expired.

Minimize the length of the leases on your original scope to reduce
the time of turnover and addreses with the wrong subnet mask. Do this
well enough in advance that all outstanding leases will have the
shorter duration when you start the conversion.

--
Matt Hickman
An H-missile doesn't care how brave you are.
Robert A. Heinlein (1907 - 1988)
_The Moon Is a Harsh Mistress_ c 1966

Pretty much No.

--
Herb Martin
"Matt" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> Pertaining to Windows 2003 Server Standard Edition, is there any way
> to change the subnet on a DHCP scope without first removing the
> existing scope? I need to go from a 24 bit subnet mask to a 22 bit
> subnet mask. If I have to remove the existing scope, how am I going
> to keep the clients from requesting addresses already in use that were
> handed out previously by the deleted scope? Thanks.
>
> PS: There is a MS KB article on this however it does not go into any
> detail. The article is at http://support.microsoft.com/?kbid=255999
>
> Matt

Using the server-side conflict detection feature could also ease this
transition.
See the server properties dialog, Advanced tab to configure this
functionality.

When turned on, the DHCP Server will attempt to ping any address it is about
to lease out to ensure that another client on the network isn't already
using it. If it receives a response, it will not hand out the address, but
will place a temporary 'bad_address' lease on it, to prevent duplicate
addresses on the network. The owning client can still come back and claim
it, however.

-Chris
--
==============================
Chris Edson
(E-Mail Removed)

This posting is provided "AS IS" with
no warranties, and confers no rights.
===============================

"Matt Hickman" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> (E-Mail Removed) (Matt) wrote in message
news:<(E-Mail Removed). com>...
> > Pertaining to Windows 2003 Server Standard Edition, is there any way
> > to change the subnet on a DHCP scope without first removing the
> > existing scope?
>
> Not that I am aware. However, you can keep your existing scope a while.
> Set the new scope up on a second DHCP server and do the conversion
> in parallel. Once complete, retire DHCP on the original server.
>
> > I need to go from a 24 bit subnet mask to a 22 bit
> > subnet mask. If I have to remove the existing scope, how am I going
> > to keep the clients from requesting addresses already in use that were
> > handed out previously by the deleted scope? Thanks.
>
> You can set up exclusions for the range of addesses that are already
> leased. You may remove that exclusion once all those leases have
> expired.
>
> Minimize the length of the leases on your original scope to reduce
> the time of turnover and addreses with the wrong subnet mask. Do this
> well enough in advance that all outstanding leases will have the
> shorter duration when you start the conversion.
>
> --
> Matt Hickman
> An H-missile doesn't care how brave you are.
> Robert A. Heinlein (1907 - 1988)
> _The Moon Is a Harsh Mistress_ c 1966

> Using the server-side conflict detection feature could also ease this
> transition.
> See the server properties dialog, Advanced tab to configure this
> functionality.

Ugggh -- using this protection feature sounds like a very poor idea.

This feature is designed to protect you against yourself or stupid
users and other admins but it cannot guarantee a clean address
since the "other" machine might not be online or always able to
answer.

It's there to protect you when you BEST efforts go awry, not
to encourage you to do it on purpose.

That said, it's a choice if you make it with open eyes and
understand it.

--
Herb Martin