Using Jetpack for Proactive Compacting

DHCP and WINS both use the Microsoft Jet database technology for their databases, and like most databases, the DHCP and WINS database files grow over time as records are added and deleted. Microsoft includes Jetpack, a database-compacting tool, in Windows 2000 and Windows NT, and I strongly recommend that you regularly run this tool against both your DHCP (dhcp.mdb) and WINS (wins.mdb) databases as part of your network-maintenance routine.

The Jetpack command's format is

jetpack <database>.mdb <tempdatabase>.mdb

For example, to compact your DHCP database, set the DHCP database directory as the current directory and stop the DHCP service. Then, issue the following command at a command prompt:

jetpack dhcp.mdb tmp.mdb

This command instructs Jetpack to use tmp.mdb as a temporary database during the compacting operation. To compact the database, Jetpack copies records from the primary database to the temporary database. After successfully copying the records, Jetpack deletes the original database and renames the temporary database, giving it the original database name. Regularly using Jetpack to compact DHCP and WINS databases not only keeps the databases small but also alerts you to potential corruption because Jetpack returns an error message if it finds major inconsistencies in a database during compaction.

If you're running DHCP or WINS in a clustered environment, you need to use a different procedure for running Jetpack. Microsoft documents this process in the article "How to Use the Jetpack Utility on a Clustered WINS/DHCP Database" (

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