Maintain the DHCP Database
Back up a DHCP database.
Key terms for this section include the following:
| Term | Definition |
|---|---|
DHCP Database | DHCP servers store DHCP lease and reservation information in database files. By default, these files are stored in the %SystemRoot%\System32\DHCP directory. |
DHCP database file types
Removing a DHCP database
Backup interval
Moving a DHCP database
You must stop the DHCP service when manually modifying the database.
DHCP Database File Types
| File | Description |
|---|---|
dhcp.mdb | This is the primary file for dhcp and contains all the scope information. |
dhcp.tmp | This is a backup copy of the dhcp that is created during indexing. |
J50.log | This file contains changes to the dhcp database before they are written. |
J50.chk | This file tells dhcp which log files are needed for recovery purposes. |
Remove a DHCP Database
Following are steps that can be taken to remove the DHCP database.
Open a command prompts and stop the DHCP service by typing net stop dhcpserver.
Remove all the files from C:\Windows\System32\DHCP.
From the command prompt, restart the service by typing net start dhcpserver.
Reconcile the DHCP scope to check for errors.
DHCP Backup Interval
There are several things you should be aware of concerning the DHCP Backup Interval.
The DHCP Database backs up every 60 minutes by default.
DHCP scopes, reservations, active leases, server options, and scope options are stored in backups.
You can change the backup interval by modifying the registry key. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DHCPServer\Parameters.
Move a DHCP Database
You may find it necessary to move the DHCP service to another server. If your DHCP has a complex configuration, you may find it easier to move the DHCP database than to manually configure the new server. This is especially true if your DHCP has a complex configuration or a large number of reservations. Moving the database eliminates the errors that are inherent when manually typing DHCP reservations, exclusions, and filters.
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