Windows XP SP2 Auto Download

You have 25000 desktops and do not have a patch roll-out strategy other than users running Windows update?

If so, you have more issues than bandwidth.

In ANY business environment, SP2 for XP should be a planned roll-out with testing done before ANY systems are updated!
A number of applications will need patches or replacement once SP2 is installed.

You will need a strategy for setting or disabling XP's "improved" firewall. By default, when SP2 is installed the firewall is enabled.

Users with auto-update enabled should have been installing SP2 this past week.

Now, you have a few options.

Start with Microsoft's download page.
There is a utility you can download to prevent Windows Update from selecting to install SP2.
A companion utility can be run to enable the installation of SP2 when you are ready.

There is a download available of the full SP2 package. It's 270+ MB.
You can download the full version and distribute it to save both bandwidth and time.

There are downloads with information on firewall settings, group policies, and a few other topics that should prove useful.

Personally, I would block access to Microsoft until you can roll-out the SP2 block utility.
Then, test SP 2 with your key applications.
Then, devise a roll-out strategy.

Chas

At this point I cannot hesitate to reccommend that you use an internal patch management system, SUS being quite effective. After all the impact of XP SP2 needs to be tested before entering a corporate environment. My own testing has identified some major issues with AV compatability and potentially some user training issues. I would not even think about allowing my clients to be updated with a major operating system revision without extensive testing, regardless of the security benefits.