For security reasons, some organizations maintain networks with no Internet connectivity. In that case, it is still possible to obtain updated catalogs, but you will first have to learn about new security bulletins by subscribing to the Microsoft Security Notification Service at the Security Web site on TechNet ( Whenever Microsoft announces a new security bulletin, you must manually download the latest catalog. You can download the Microsoft Update catalog from the Windows Update Web site (

If you choose to manually download the catalog, you must manually keep it up to date. Failing to download the most recent catalog will result in clients not receiving the most recent security updates.

Copy the latest catalog to the local catalog location you specified during Setup. Once a day, the synchronization host runs its scheduled program and checks the local catalog location for a new catalog. If the catalog in the local catalog location is more recent than the catalog in the PkgSource folder, the synchronization host copies the new catalog to the PkgSource folder and then updates all of the distribution points with the Microsoft Updates Tool package.