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Another 291 exam objective you'll find is the ability or the topic of managing DHCP databases. And it's something that really in a real world you don't have to do too much because DHCP is such a dynamic entity, it's such a dynamic service and the database is a dynamic database and it's easily re-creatable as you've just seen. But we want to at least recognize how to manage some of the DHCP databases or to manage the DHCP database. There are 3 methods you can use, you can make use of automatic backups. Automatic backups occur by default every 60 minutes. You can use manual backups, this is done through the MMC console and you can also backup DHCP information using the Windows backup. And Windows backup if you backup the system state it will also backup the DHCP database. We want to take a look at, because this is the only one that really needs button pushing intervention on our part. The manual backups, which is done through the MMC console. And it's really very straightforward procedure. First of all you open up the DHCP console and then on the properties of the server you select the server whose database you're going to backup and first of all lets look at the properties of this server on the advanced tab. Here is the backup path. Windows folder, the system root folders, System32, DHCP and then backup. We can select a different folder although I don't really recommend it, it's something that the default backup path is just fine in 999 times out of 1000. To manually backup the contents of the DHCP database, you right click and choose backup. Select the backup path, you can use the same one that the default is in which is again just fine, click on OK and after couple of seconds usually, you will have the database backed up. So that's it. What just got backed up, you may be wondering. All the scopes, all the reservations you've set, all the active leases, the information about what is currently leased out gets backed up. Any options that you've set including server options, scope options, reservation options and class options, so in other words anything that's crucial to the operation of DHCP gets backed up. To restore the database open up your DHCP consoles, the databases become corrupted, we can restore from backup right click and restore. Where are the backed up files? They're in the backup directory here, service must be stopped and restarted, do this now? Yes. The console's going to go out and find the DHCP files, import them stop and start the service and after that we should be right as rain and we're done. So I've just restored from backup and indeed everything looks the same as it should, I've got the same scope options, got the same leases if there were leases that were out then those would be listed as well. So in other words all the information, our reservations, everything will be included when we backup. Now if you're wondering about changing the default interval, which automatically is done every 60 minutes and this just won't suit your needs at all then you can change that but you have to open up the registry and edit a registry key that defines the behavior of DHCP. Start, run, regedit, opens up the registry editor and then it's here. It's under H key local machine and then it should be under system, current control set services, and then look for the DHCP server key parameters and then in the parameters folder, in the parameters key you should see a backup interval. And here you can set this value of 3c is the hexadecimal equivalent of 60 minutes. So that's where you can set it, it's just not really necessary under any kind of normal environment to do this because again as I mentioned at the beginning you can setup a DHCP database in no time at all by just configuring your scopes again. So worst-case scenario, your DHCP blows up but it's just not that hard to recover the DHCP disaster.