Shorter DHCP lease for laptops

I originally posted this looking for help on how to assign a DHCP Class ID
via group policy but since I did not receive a single response, I got to
thinking maybe it just can't be done.

SO: I'll start over with exactly what I'm trying to accomplish. Maybe I'm
on completely the wrong track. Any thoughts / links on this will be
appreciated.

I have many salespeople that travel 98% of the time. Since I'm getting low
on IP addresses, I want to make the sales laptops DHCP lease for only one
day so when these people logoff and go on the road, their IP will be
released back into the pool (after 24 hours) instead of them taking their IP
with them for the 16 days that everyone else (desktops) gets a lease for.

I have already created the Class ID on the DHCP server with the exact scope
options I want and it works perfect when I manually assign the Class ID to a
test laptop.

NOW all I need is a way to assign the class ID to all the laptops without
"touching" each one individually. I have moved all the
laptop machine accounts into their own OU.

I thought I could do it via Group Policy but maybe I was wrong.

Anyone know how to accomplish this?

Hello SuperK,

Why not just changing the scopes for all machines? Saves you a lot of effort
and will also work. Set the scope to the normal working time of the static
users, 12 hours should be fine. After 50% of the leasetime the client will
renew the ip address, that will not much work for the server.

Best regards

Meinolf Weber
Disclaimer: This posting is provided "AS IS" with no warranties, and confers
no rights.
** Please do NOT email, only reply to Newsgroups
** HELP us help YOU!!! http://www.blakjak.demon.co.uk/mul_crss.htm


> I originally posted this looking for help on how to assign a DHCP
> Class ID via group policy but since I did not receive a single
> response, I got to thinking maybe it just can't be done.
>
> SO: I'll start over with exactly what I'm trying to accomplish. Maybe
> I'm on completely the wrong track. Any thoughts / links on this will
> be appreciated.
>
> I have many salespeople that travel 98% of the time. Since I'm getting
> low on IP addresses, I want to make the sales laptops DHCP lease for
> only one day so when these people logoff and go on the road, their IP
> will be released back into the pool (after 24 hours) instead of them
> taking their IP with them for the 16 days that everyone else
> (desktops) gets a lease for.
>
> I have already created the Class ID on the DHCP server with the exact
> scope options I want and it works perfect when I manually assign the
> Class ID to a test laptop.
>
> NOW all I need is a way to assign the class ID to all the laptops
> without
> "touching" each one individually. I have moved all the
> laptop machine accounts into their own OU.
> I thought I could do it via Group Policy but maybe I was wrong.
>
> Anyone know how to accomplish this?
>

Thanks for your thoughts Meinolf,

.. . . but I have over 850 desktop DHCP clients and 350 laptop DHCP clients.
If I set all to 1 day that would create an awful lot of unnecessary network
traffic. At T1 (12 hours) over 1200 PC's would be trying to renew their
leases, then at T2 (approx 21 hours) they all would once again try to renew.
I know these requests would be staggered, but I'm always trying to reduce
network traffic when possible.

This is actually a MS best practice. Longer leases when you have plenty of
spare IP's in your pool and/or a stable infrastructure and shorter leases
when you're low on IP's and/or constantly changing infrastructure. I just
can't locate any details on how it's implemented.

ACTUALLY, how would I set the class ID on a number of boxes for whatever
reason, not necessarily leases? We use DHCP to ELIMINATE manual settings on
PC's in the first place. If we were to take advantage of Class ID's for any
other scope options, it kind of defeats the purpose to have to set them on
each individual machine.

Anything you can offer will be appreciated.


"Meinolf Weber [MVP-DS]" <meiweb(nospam)@gmx.de> wrote in message
news:(E-Mail Removed) .com...
> Hello SuperK,
>
> Why not just changing the scopes for all machines? Saves you a lot of
effort
> and will also work. Set the scope to the normal working time of the static
> users, 12 hours should be fine. After 50% of the leasetime the client will
> renew the ip address, that will not much work for the server.
>
> Best regards
>
> Meinolf Weber
> Disclaimer: This posting is provided "AS IS" with no warranties, and
confers
> no rights.
> ** Please do NOT email, only reply to Newsgroups
> ** HELP us help YOU!!! http://www.blakjak.demon.co.uk/mul_crss.htm
>
>
> > I originally posted this looking for help on how to assign a DHCP
> > Class ID via group policy but since I did not receive a single
> > response, I got to thinking maybe it just can't be done.
> >
> > SO: I'll start over with exactly what I'm trying to accomplish. Maybe
> > I'm on completely the wrong track. Any thoughts / links on this will
> > be appreciated.
> >
> > I have many salespeople that travel 98% of the time. Since I'm getting
> > low on IP addresses, I want to make the sales laptops DHCP lease for
> > only one day so when these people logoff and go on the road, their IP
> > will be released back into the pool (after 24 hours) instead of them
> > taking their IP with them for the 16 days that everyone else
> > (desktops) gets a lease for.
> >
> > I have already created the Class ID on the DHCP server with the exact
> > scope options I want and it works perfect when I manually assign the
> > Class ID to a test laptop.
> >
> > NOW all I need is a way to assign the class ID to all the laptops
> > without
> > "touching" each one individually. I have moved all the
> > laptop machine accounts into their own OU.
> > I thought I could do it via Group Policy but maybe I was wrong.
> >
> > Anyone know how to accomplish this?
> >
>
>

In news:(E-Mail Removed),
SuperK <(E-Mail Removed)>, posted the following:
> Thanks for your thoughts Meinolf,
>
> . . . but I have over 850 desktop DHCP clients and 350 laptop DHCP
> clients. If I set all to 1 day that would create an awful lot of
> unnecessary network traffic. At T1 (12 hours) over 1200 PC's would be
> trying to renew their leases, then at T2 (approx 21 hours) they all
> would once again try to renew. I know these requests would be
> staggered, but I'm always trying to reduce network traffic when
> possible.
>
> This is actually a MS best practice. Longer leases when you have
> plenty of spare IP's in your pool and/or a stable infrastructure and
> shorter leases when you're low on IP's and/or constantly changing
> infrastructure. I just can't locate any details on how it's
> implemented.
>
> ACTUALLY, how would I set the class ID on a number of boxes for
> whatever reason, not necessarily leases? We use DHCP to ELIMINATE
> manual settings on PC's in the first place. If we were to take
> advantage of Class ID's for any other scope options, it kind of
> defeats the purpose to have to set them on each individual machine.
>
> Anything you can offer will be appreciated.
>

I believe you've posted to a couple of groups with this question, but I
forget which one, without searching through. What other groups did you post
to? It may probably be a good idea in the future to cross-post instead of
multiposting, to make it easier for you and us. This way all responses will
go to all the groups simultaneously that they were originally posted in and
multiple folks can collaborate cross-platform.

I believe you already had a response from Marcin in one of the other groups,
concerning your script or batch not running as a logon script not running
because the users are not local admins.I believe he already mentioned it has
to be a Computer Startup script set in a GPO for the Laptop OUs, and
specifically not "logon" script.

That said, here is an excerpt from a link that may help you:
===
Because it is tedious to manually assign class IDs to a large number of
computers, there are a couple of alternatives.

1. If doing an unattended installation you can use the following value to
set the ClassID in the [MS_TCPIP parameters] section of the Unattend.txt
file.

DHCPClassId Value: string Optional Specifies the DHCP class ID. For example:
DHCPClassId = name

2. If you have already completed the install you could do the following:

- Create the following batch file "classid.bat": if %classid%==hug goto end
set classid=hug ipconfig /setclassid "Local Area Connection" [value] :end

Replace the value variable with the class ID you wish to set.

- Create or modify an existing Group Policy to include the CLASSID.BAT as a
startup script for the computers that will receive the classid.

- Save the CLASSID.BAT to the specific GPO script folder inside the SYSVOL
on a DC (will be replicated to the other DCs automatically).

From:
http://forums.windowsitpro.com/web/f...&enterthread=y

Additional reading:

How to Configure DHCP Class ID on a Windows 2000 DHCP Client
http://support.microsoft.com/kb/235272

Manage Options and Classes
http://technet.microsoft.com/en-us/l.../cc783707.aspx

===

I hope that helps.

--
Ace

This posting is provided "AS-IS" with no warranties or guarantees and
confers no rights.

Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSA Messaging, MCT
Microsoft Certified Trainer
(E-Mail Removed)

For urgent issues, you may want to contact Microsoft PSS directly. Please
check http://support.microsoft.com for regional support phone numbers.