Backing up the DHCP database

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Backing up the DHCP database

Maintaining a backup of the DHCP database protects you from data loss if the DHCP database is lost (for example, due to hard disk failure) or becomes corrupted. There are three backup methods supported by the DHCP Server service:

  • Synchronous backups that occur automatically. The default backup interval is 60 minutes.

  • Asynchronous (manual) backups, performed by using the Backup command on the DHCP console. For more information about asynchronous backups, see Back up the DHCP database.

  • Backups using Windows Backup (ntbackup.exe) or non-Microsoft backup software. For more information about Windows Backup, see Backup.

When a synchronous or asynchronous backup occurs, the entire DHCP database is saved, including the following:

  • All scopes, including superscopes and multicast scopes

  • Reservations

  • Leases

  • All options, including server options, scope options, reservation options, and class options

  • All registry keys and other configuration settings (for example, audit log settings and folder location settings) set in DHCP server properties. These settings are stored in the following registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DHCPServer\Parameters

    To back up this subkey, open Registry Editor, and save the specified key to a text file. For more information, see Open Registry Editor and Import or Export Registry Keys.

Note

  • The DNS dynamic update credentials (user name, domain, and password) that the DHCP server uses when registering DHCP client computers in DNS are not backed up with any backup method.

Backup locations

The default DHCP database backup path is systemroot\System32\Dhcp\Backup. You can change the database backup folder by selecting a different local folder during a manual backup or by changing the backup folder location in DHCP server properties. For more information, see Set the DHCP database backup path.

When planning your backup strategy, consider the following:

  • Synchronous backups are performed while the DHCP service is running. Similarly, when you perform asynchronous (manual) backups, you do not need to stop the DHCP service unless you are moving your database to a new server. For more information, see Move a DHCP database to another server.

  • The backup folder location must be a local path.

Notes

  • This topic assumes that the DHCP database and its backup directories are located on the default drive and path locations.

  • The default automatic database backup interval is 60 minutes. You can change the automatic backup interval through the following registry key:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DHCPServer\Parameters\BackupInterval

    Caution

    • Incorrectly editing the registry may severely damage your system. Before making changes to the registry, you should back up any valued data on the computer.

  • Do not store DHCP server backups on the same hard drive on which the DHCP service is installed, and make sure that the access control list (ACL) for the backup folder contains only the Administrators group and the DHCP Administrator group as members. In addition to performing manual backups, back up to other locations, such as a tape drive, and make sure that unauthorized persons do not have access to your backup copies. You can use Windows Backup for this purpose. For more information, see Best practices for Backup.