Table Of Contents<\/h3>\n\n- 1. DHCP Backup & Restore Introduction<\/a><\/dt>\n
- \n
\n- 1.1. DHCP Backup Basics 101<\/a><\/dt>\n
- 1.2. DHCP Backup Basics 201<\/a><\/dt>\n
- 1.3. DHCP Backup Basics 301<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 2. Backup & Restore (GUI & CLI)<\/a><\/dt>\n
- \n
\n- 2.1. Backup via GUI<\/a><\/dt>\n
- 2.2. Restore via GUI<\/a><\/dt>\n
- 2.3. Backup via CLI<\/a><\/dt>\n
- 2.4. Restore via CLI<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 3. Export & Import (CLI Only)<\/a><\/dt>\n
- \n
\n- 3.1. Export<\/a><\/dt>\n
- 3.2. Import<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 4. Dump & Exec (CLI Only)<\/a><\/dt>\n
- \n
\n- 4.1. Dump<\/a><\/dt>\n
- 4.2. Exec<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 5. Bonus: Extra DHPC Management Tricks<\/a><\/dt>\n
- \n
\n- 5.1. Trick #1<\/a><\/dt>\n
- 5.2. Trick #2<\/a><\/dt>\n
- 5.3. Trick #3<\/a><\/a><\/dt>\n
- 5.4. Trick #4<\/a><\/dt>\n
- 5.5. Trick #5<\/a><\/dt>\n
- 5.6. Trick #6<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 6. Summary<\/a><\/dt>\n<\/dl>\n<\/div>\n
1. DHCP Backup & Restore Introduction<\/h2>\n
It goes without saying that it’s important to keep backups of critical data, and DHCP is definitely one of those critical items. It’s important to have good backups available because you never know when unforeseen disaster is going to strike (i.e. data corruption, hardware failure, etc). While my own backup preference may seem a little overkill to some (I keep a backup, an export and<\/strong><\/em> \u00a0occasionally a dump file), I like the peace of mind of knowing that I’ve got multiple options, just in case<\/em> something ever goes wrong.<\/p>\nNOTE 1:<\/em><\/span> \u00a0It’s assumed that you have Administrative rights (and any necessary remote access to source and destination servers) to perform the steps laid out in this article. Membership in the Administrators group or the DHCP Administrators group is the minimum required permissions in order to successfully complete these procedures.<\/p>\n<\/a>NOTE 2:<\/em><\/span> \u00a0It’s assumed that you already have a DHCP server configured and running.<\/p>\nLet’s get started with some basics first, then I’ll cover all the details of the pertinent info that you’ll want to be aware of as we continue to move forward in the article.<\/p>\n
1.1. DHCP Backup Basics 101<\/h3>\n
To keep things simple, I’m going to present some of Microsoft’s info in my own terms and from my own perspective because I’d like to make this info as easy to understand as possible, for both experienced admins and fresh admins alike. For instance, there are basically two methods of backups that you should be aware of: automatic (“synchronous”) and manual (“asynchronous”).<\/p>\n
Anytime you setup a Windows DHCP server, backups will automatically occur every 60 minutes by default, and they’re always saved to the following folder:<\/p>\n
C:\\Windows\\System32\\DHCP\\Backup<\/pre>\nKeep in mind that only one backup copy is stored at any given time (the existing backup is overwritten every 60 minutes with the latest backup copy), so it’s recommended that you keep a copy of this database somewhere other than the default location (i.e. Copy the folder to a file share on your storage server).<\/p>\n
NOTE:<\/em><\/span> \u00a0The DHCP database backup folder location must be a local path. You can copy the backup to a network location after it’s completed, but the backups have to be saved to a local path first.<\/p>\nAlso, if you’d like to change the backup time interval, you can either set it with the following command (subsitute “60” with whatever time in minutes you’d like to adjust it to):<\/p>\n
netsh dhcp server set databasebackupinterval 60<\/pre>\nOr you can modify the following registry key:<\/p>\n
HKLM\\SYSTEM\\CurrentControlSet\\Services\\DHCPServer\\Parameters\\BackupInterval<\/pre>\n<\/a>If you’d like to maintain extra or multiple copies of your DHCP database, you can either manually copy the folder at whatever time interval you prefer, you could create a scheduled task (covered in Step 5<\/a><\/strong>), or you could use something like RoboCopy<\/a><\/em><\/strong> \u00a0(Or a combination of a scheduled task and RoboCopy! This will be covered in Step 5.6.4<\/a><\/strong>).<\/p>\n1.2. DHCP Backup Basics 201<\/h3>\n
When a DHCP backup occurs (whether it’s automatic or manual), the entire DHCP database is saved, including the following data\/information:<\/p>\n
\n- \u00a0All scopes, including superscopes and multicast scopes<\/li>\n
- \u00a0Reservations<\/li>\n
- \u00a0Leases<\/li>\n
- \u00a0All options, including server options, scope options, reservation options, and class options<\/li>\n
- \u00a0All related registry keys and other configuration settings<\/li>\n<\/ul>\n
NOTE:<\/em><\/span> \u00a0If you use DNS dynamic update credentials, this information is not saved as part of the backup; so you’ll have to manually re-enter these credentials again if you ever restore from a backup. This can be done via CLI, using the following command syntax:<\/p>\nnetsh dhcp server set dnscredentials <username> <domain> <password><\/pre>\nOr via the DHCP MMC (DHCP Management Console):<\/p>\n
Right-click “IPv4” under the server you want to add the credentials to, choose “Properties”, click the “Advanced” tab, click the “Credentials…” button, then enter the appropriate information. Refer to Figure 0 below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-00_dhcp_dyndns_creds.jpg\")
<\/a>Figure 0: Setting Dynamic DNS Credentials via GUI<\/figcaption><\/figure>\n<\/a><\/p>\n1.3. DHCP Backup Basics 301<\/h3>\n
There are three main groups of commands that are used when backing up DHCP server database information from CLI (all of which are associated with the “Netsh” command-line tool). I’ll list them and give a brief breakdown of each set of commands.<\/p>\n
NOTE:<\/em><\/span> \u00a0There is a lot<\/em><\/strong> of information online pertaining to each of these commands\/options! I’ve extensively researched them all and will provide my perspective on what I’ve found. For now, I’ll just list them along with a brief explanation of each, and I’ll provide more details and examples beginning with Step 2.3<\/a><\/strong>.<\/p>\n1.3.1. “Backup” & “Restore”<\/h4>\n
These are the equivalent of the GUI commands for backup and restore (the GUI commands are covered in more detail in Step 2<\/a><\/strong>). Command syntax is as follows:<\/a><\/p>\nnetsh dhcp server backup <backup folder location><\/pre>\nnetsh dhcp server restore <backup folder location><\/pre>\n1.3.2. “Export” & “Import”<\/h4>\n
This is the most widely used set of commands for backing up and restoring a DHCP server database, and it’s the “best practice” and commonly recommended method referenced by Microsoft. As you could likely expect, there can arise some confusion about the difference between “Backup & Restore” vs “Export & Import”. The key difference to be aware of is this: “Backup” & “Restore” can be used to backup & restore a DHCP server database from and to the same OS version, whereas “Export” & “Import” can be used for both backing up and restoring from and to the same server, as well as between different server versions.<\/p>\n
To re-iterate and clarify this, if you want to backup a Windows Server 2008 R2 database and restore it to either the same server or to a different Windows Server 2008 R2 installation, you can use “backup & restore” or<\/strong><\/em> \u00a0“export & import”. However, if you want to backup a Windows Server 2008 R2 database and restore it to a Windows Server 2012 R2 server installation, you’ll want to only<\/strong><\/em> use the “export” & “import” commands. Export\/Import will be covered in more detail in Step 3<\/a><\/strong>. Command syntax is as follows:<\/p>\nnetsh dhcp server export <backup folder location & filename> <scope info to export> (use \"all\" for ALL scope info, or specify specific scope(s))<\/pre>\n<\/a><\/p>\nnetsh dhcp server import <backup folder location & filename> <scope info to import> (use \"all\" for ALL scope info, or specify specific scope(s))<\/pre>\n1.3.3. “Dump” & “Exec”<\/h4>\n
The “dump” command is essentially used to export the configuration info of a server (not<\/strong><\/em> \u00a0the entire database), and it’s generally only used for advanced troubleshooting and\/or configuration scenarios. While you could use these commands to export\/import configuration info from one server to another (with the same OS version or different OS version), I personally would only recommend using it to make changes to the same server that the information was exported from (or at least to the same OS version if your primary DHCP server dies).<\/p>\nLet me help clarify this some more: There are multiple scenarios where using dump and exec can be handy. One example is that you could manually create a template file (a simple .txt file with all of your DHCP configuration info) and then use exec to import that configuration info into one or more servers. This process can save some configuration and deployment time in a “multiple DHCP server deployment” scenario.<\/p>\n
Another example of where the dump command can be handy is if you’d like to make a change to a DHCP scope. For example, if you’d like to change the subnet mask of a scope, this can’t be done without deleting the scope and recreating it. However, if there are a lot of customizations in the scope (like reservations and scope options), it’s going to be a lot of extra work to recreate all of that information. But with the dump command, you can export the configuration info for that specific scope, make modifications, then safely delete the scope from the DHCP MMC, and finally re-import all of the updated configuration info using the exec command. Dump\/Exec will be covered in more detail in Step 4<\/a><\/strong>. Command syntax is as follows:<\/p>\n(Dump – two examples)<\/p>\n
netsh dhcp server scope <scopeaddress> dump > <backup folder location & filename><\/pre>\nnetsh dhcp server dump > <backup folder location & filename><\/pre>\n(Exec)<\/p>\n
netsh exec <path location of dump file><\/pre>\nNOTE 1:<\/em><\/span> \u00a0The single “>” after “dump” acts as a redirect which outputs all of the configuration info to a file.<\/p>\n<\/a>NOTE 2:<\/em><\/span> \u00a0Before using the dump command, it’s recommended that you verify and reconcile any database inconsistencies (so your dump file is “clean”). I’ll cover “reconcile” and other cool tricks in more detail in Step 5<\/a><\/strong>.<\/p>\n<\/a><\/p>\n2. Backup & Restore (GUI & CLI)<\/h2>\n
In this first main section, I’ll detail the steps for doing a backup and restore from both the GUI and from the command line. Let’s start with the GUI steps first.<\/p>\n
2.1. Backup via GUI<\/h3>\n
The first backup option I’ll cover is a full backup from the GUI, via the DHCP management console. Again, as stated earlier in the article, this type of backup is ideal for either restoring to the same server and OS version, or to another server running the same OS version. On the server that you want to backup DHCP from, launch the DHCP MMC by navigating to it in the Administrative Tools menu. Refer to Figure 1 below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-01_dhcp_mmc.jpg\")
<\/a>Figure 1: DHCP MMC via Admin Tools menu<\/figcaption><\/figure>\nAfter the console window opens, your server should be listed. If not, right-click on “DHCP” and choose “Add Server”. A new window opens and your server should be listed in the box under “This authorized DHCP server:”. Select it and click “OK”. Refer to Figure 2a and 2b below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-02a_dhcp_mmc_add-server.jpg\")
<\/a>Figure 2a: Add your DHCP server<\/figcaption><\/figure>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-02b_dhcp_mmc_add-server.jpg\")
<\/a>Figure 2b: Select the appropriate DHCP server<\/figcaption><\/figure>\nOnce your server has been added to the list, right-click on it and choose “Backup”. A “Browse For Folder” window will open, and it will have the default backup folder location already selected (C:\\Windows\\System32\\dhcp\\backup); Click “OK”. Refer to Figure 3a and 3b below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-03a_dhcp_mmc_backup.jpg\")
<\/a>Figure 3a: Backup via the GUI<\/figcaption><\/figure>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-03b_dhcp_mmc_backup.jpg\")
<\/a>Figure 3b: Selecting the default backup folder location<\/figcaption><\/figure>\nUnfortunately, the Windows OS does not give you any prompt or indication that the backup “completed successfully!”. However, you can open Windows Explorer and navigate to the backup folder and verify that the files have the appropriate date and timestamp. Refer to Figure 3c below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-03c_dhcp_mmc_backup-complete-.jpg\")
<\/a>Figure 3c: Backup complete (verify date\/timestamps)<\/figcaption><\/figure>\n<\/a>Remember to store a copy of this backup somewhere else besides the default backup location (as previously referenced in the Note in Step 1.1<\/a><\/strong>).<\/p>\n2.2. Restore via GUI<\/h3>\n
Before doing the restore, I would recommend copying the folder from the saved backup (located on your storage server for instance; as referenced in step 1.1) to the desktop of the user profile of the admin account that you’re using to logon to the DHCP server. In my example, I’ve stored a copy of the backup in a folder named “dhcp”. Refer to Figure 4 below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-04_dhcp_backup_copy_desktop.jpg\")
<\/a>Figure 4: DHCP backup copied to desktop<\/figcaption><\/figure>\nNOTE:<\/em><\/span> \u00a0Before running the restore, if the old server will no longer be used to host DHCP services, you should either stop and disable the DHCP Server service, de-activate the scopes, or unauthorize the server (I would recommend this last option I mentioned). Refer to Figure 5a and 5b below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-05a_dhcp_mmc_unauthorize.jpg\")
<\/a>Figure 5a: Unauthorize old DHPC server<\/figcaption><\/figure>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-05b_dhcp_mmc_unauthorize.jpg\")
<\/a>Figure 5b: Confirm unauthorize old DHPC server<\/figcaption><\/figure>\nNOTE:<\/em><\/span> \u00a0I would also recommend verifying the correct permissions on the backup folder that you copied to the desktop before<\/strong><\/em> \u00a0beginning the restore process (Refer to Figure 6f<\/a><\/strong> further down).<\/p>\nNow it’s time to restore to the new server. To restore a backup, you would basically follow the same steps that were referenced in section 2.1, but choose “restore” instead of “backup”. As referenced in figure 2a and 2b, launch the DHCP MMC and make sure your new server is listed (if it’s not, add it).<\/p>\n
Once your server is available in the DHPC MMC, you should see some red down arrow emblems<\/em> \u00a0over the icons for IPv4 and IPv6 (indicating that the server is connected but not authorized). Authorize the new server by right-clicking on it and choosing “Authorize”. Refer to Figure 5c below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-05c_dhcp_mmc_destination_server.jpg\")
<\/a>Figure 5c: Authorize the new server<\/figcaption><\/figure>\nIt will take a few moments for the server authorization to fully take effect. You can click “Action” from the menu and choose “Refresh” to update the status. When it’s successfully updated, you should see the emblems on the icons change from red down arrows<\/em> to green check marks<\/em> (indicating that the server is connected and active). Refer to Figure 5d below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-05d_dhcp_mmc_server_authorized.jpg\")
<\/a>Figure 5d: Server successfully authorized<\/figcaption><\/figure>\nIf the status doesn’t successfully update, open the Services MMC (via Administrative Tools) and restart the DHCP Server service (the far right toolbar button, or right-click the service and choose “Restart”). Once the service has been successfully restarted, it should look like this (Refer to Figure 5e below):<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-05e_dhcp_mmc_dhcp_service.jpg\")
<\/a>Figure 5e: DHCP Server service successfully restarted<\/figcaption><\/figure>\nBe sure to check the console again and verify that the server is authorized (refer back to Figure 5d). Once the server is successfully authorized, you can perform a restore. Right-click your server and choose “Restore…”. Refer to Figure 6a below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-06a_dhcp_mmc_restore.jpg\")
<\/a>Figure 6a: Restoring the DHCP backup<\/figcaption><\/figure>\nYou will be prompted that the service must be restarted for the changes to take effect (this is normal); choose “Yes”. Refer to Figure 6b below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-06b_dhcp_mmc_restore.jpg\")
<\/a>Figure 6b: Prompt for restart of services<\/figcaption><\/figure>\nOnce the backup has been successfully restored, you’ll see a confirmation message. Refer to Figure 6c below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-06c_dhcp_mmc_restore.jpg\")
<\/a>Figure 6c: Database successfully restored<\/figcaption><\/figure>\nNOTE:<\/em><\/span> \u00a0There are times when certain variables in the restore process are not quite right, which can cause various error messages. For instance, if the backup folder on the desktop does not have proper permissions configured, you could see messages like these (Refer to Figure 6d and 6e below):<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-06d_dhcp_insufficient_perms.jpg\")
<\/a>Figure 6d: Insufficient permissions on the backup folder<\/figcaption><\/figure>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-06e_dhcp_cannot_find_file.jpg\")
<\/a>Figure 6e: Cannot find the file specified (permissions issue)<\/figcaption><\/figure>\n<\/a>Sometimes DHCP will prompt you that it can attempt to repair the permissions. But if that fails, or you need to verify\/set them manually, right-click on the backup folder on the desktop, choose “Properties”, click the “Security” tab, then click the “Edit” button. Verify that the user account you’re currently logged on with has “Allow” permissions for “Full control”. Refer to Figure 6f below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-06f_dhcp_setting_perms.jpg\")
<\/a>Figure 6f: Verifying proper folder permissions<\/figcaption><\/figure>\nTry the restore again after you’ve set the correct permissions on the folder that you’re restoring from.<\/p>\n
If you ever get a service error message (Refer to Figure 6g below), you can wait a moment, restart the DHCP Server service, then try again:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-06g_dhcp_service_error.jpg\")
<\/a>Figure 6g: DHCP Server service error<\/figcaption><\/figure>\n<\/a>When the restore has completed successfully, you’ll be able to verify that all of the database information exists under “IPv4” (and “IPv6” if applicable) in your DHCP MMC.<\/p>\n2.3. Backup via CLI<\/h3>\n
This is essentially the same procedure as in step 2.1, but done entirely from CLI using Netsh. The backup process via CLI is fast and simple compared to the GUI method (granted, neither method is difficult<\/em>, but the CLI method is much shorter in terms of steps involved, and more efficient in my opinion). This process can be done by remotely connecting to the DHCP server via a command prompt, but I prefer to directly logon to the server and run the commands from the server’s CLI.<\/p>\nOpen an admin command prompt by searching for “cmd” or “command prompt” via the Start menu, right-click on the search result, and choosing “Run as administrator”. Refer to Figure 7a below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-07a_cmd_search.jpg\")
<\/a>Figure 7a: Command Prompt via searching from Start menu<\/figcaption><\/figure>\nNOTE:<\/em><\/span> \u00a0If you’re prompted by UAC, click “Yes”. Refer to Figure 7b below:<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-07b_uac.jpg\")
<\/a>Figure 7b: UAC prompt<\/figcaption><\/figure>\nOnce the command prompt is open, doing a backup is as simple as typing the following command syntax:<\/p>\n
netsh dhcp server backup <backup folder location><\/pre>\nIn the example below, I backup the database to a folder named “dhcp” under “C:\\Users\\Admin\\Desktop\\” (Refer to Figure 8 below):<\/p>\n![\"\"](\"http:\/\/www.systemcodegeeks.com\/wp-content\/uploads\/2017\/01\/scg_shuey_005-08_cli_backup.jpg\")
<\/a>Figure 8: CLI backup<\/figcaption><\/figure>\nThat’s it! Much faster via CLI!<\/p>\n
Before you proceed to the next section, if you’re no longer going to use your old server to provide DHCP services, unauthorize the server by typing the following command syntax:<\/p>\n
netsh dhcp delete server <ServerDNS> <ServerIP><\/pre>\n
- \n
- 1.1. DHCP Backup Basics 101<\/a><\/dt>\n
- 1.2. DHCP Backup Basics 201<\/a><\/dt>\n
- 1.3. DHCP Backup Basics 301<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 2. Backup & Restore (GUI & CLI)<\/a><\/dt>\n
- \n
- \n
- 2.1. Backup via GUI<\/a><\/dt>\n
- 2.2. Restore via GUI<\/a><\/dt>\n
- 2.3. Backup via CLI<\/a><\/dt>\n
- 2.4. Restore via CLI<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 3. Export & Import (CLI Only)<\/a><\/dt>\n
- \n
- \n
- 3.1. Export<\/a><\/dt>\n
- 3.2. Import<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 4. Dump & Exec (CLI Only)<\/a><\/dt>\n
- \n
- \n
- 4.1. Dump<\/a><\/dt>\n
- 4.2. Exec<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 5. Bonus: Extra DHPC Management Tricks<\/a><\/dt>\n
- \n
- \n
- 5.1. Trick #1<\/a><\/dt>\n
- 5.2. Trick #2<\/a><\/dt>\n
- 5.3. Trick #3<\/a><\/a><\/dt>\n
- 5.4. Trick #4<\/a><\/dt>\n
- 5.5. Trick #5<\/a><\/dt>\n
- 5.6. Trick #6<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 6. Summary<\/a><\/dt>\n<\/dl>\n<\/div>\n
1. DHCP Backup & Restore Introduction<\/h2>\n
It goes without saying that it’s important to keep backups of critical data, and DHCP is definitely one of those critical items. It’s important to have good backups available because you never know when unforeseen disaster is going to strike (i.e. data corruption, hardware failure, etc). While my own backup preference may seem a little overkill to some (I keep a backup, an export and<\/strong><\/em> \u00a0occasionally a dump file), I like the peace of mind of knowing that I’ve got multiple options, just in case<\/em> something ever goes wrong.<\/p>\n
NOTE 1:<\/em><\/span> \u00a0It’s assumed that you have Administrative rights (and any necessary remote access to source and destination servers) to perform the steps laid out in this article. Membership in the Administrators group or the DHCP Administrators group is the minimum required permissions in order to successfully complete these procedures.<\/p>\n
<\/a>NOTE 2:<\/em><\/span> \u00a0It’s assumed that you already have a DHCP server configured and running.<\/p>\n
Let’s get started with some basics first, then I’ll cover all the details of the pertinent info that you’ll want to be aware of as we continue to move forward in the article.<\/p>\n
1.1. DHCP Backup Basics 101<\/h3>\n
To keep things simple, I’m going to present some of Microsoft’s info in my own terms and from my own perspective because I’d like to make this info as easy to understand as possible, for both experienced admins and fresh admins alike. For instance, there are basically two methods of backups that you should be aware of: automatic (“synchronous”) and manual (“asynchronous”).<\/p>\n
Anytime you setup a Windows DHCP server, backups will automatically occur every 60 minutes by default, and they’re always saved to the following folder:<\/p>\n
C:\\Windows\\System32\\DHCP\\Backup<\/pre>\n
Keep in mind that only one backup copy is stored at any given time (the existing backup is overwritten every 60 minutes with the latest backup copy), so it’s recommended that you keep a copy of this database somewhere other than the default location (i.e. Copy the folder to a file share on your storage server).<\/p>\n
NOTE:<\/em><\/span> \u00a0The DHCP database backup folder location must be a local path. You can copy the backup to a network location after it’s completed, but the backups have to be saved to a local path first.<\/p>\n
Also, if you’d like to change the backup time interval, you can either set it with the following command (subsitute “60” with whatever time in minutes you’d like to adjust it to):<\/p>\n
netsh dhcp server set databasebackupinterval 60<\/pre>\n
Or you can modify the following registry key:<\/p>\n
HKLM\\SYSTEM\\CurrentControlSet\\Services\\DHCPServer\\Parameters\\BackupInterval<\/pre>\n
<\/a>If you’d like to maintain extra or multiple copies of your DHCP database, you can either manually copy the folder at whatever time interval you prefer, you could create a scheduled task (covered in Step 5<\/a><\/strong>), or you could use something like RoboCopy<\/a><\/em><\/strong> \u00a0(Or a combination of a scheduled task and RoboCopy! This will be covered in Step 5.6.4<\/a><\/strong>).<\/p>\n
1.2. DHCP Backup Basics 201<\/h3>\n
When a DHCP backup occurs (whether it’s automatic or manual), the entire DHCP database is saved, including the following data\/information:<\/p>\n
- \n
- \u00a0All scopes, including superscopes and multicast scopes<\/li>\n
- \u00a0Reservations<\/li>\n
- \u00a0Leases<\/li>\n
- \u00a0All options, including server options, scope options, reservation options, and class options<\/li>\n
- \u00a0All related registry keys and other configuration settings<\/li>\n<\/ul>\n
NOTE:<\/em><\/span> \u00a0If you use DNS dynamic update credentials, this information is not saved as part of the backup; so you’ll have to manually re-enter these credentials again if you ever restore from a backup. This can be done via CLI, using the following command syntax:<\/p>\n
netsh dhcp server set dnscredentials <username> <domain> <password><\/pre>\n
Or via the DHCP MMC (DHCP Management Console):<\/p>\n
Right-click “IPv4” under the server you want to add the credentials to, choose “Properties”, click the “Advanced” tab, click the “Credentials…” button, then enter the appropriate information. Refer to Figure 0 below:<\/p>\n
<\/a>Figure 0: Setting Dynamic DNS Credentials via GUI<\/figcaption><\/figure>\n <\/a><\/p>\n
1.3. DHCP Backup Basics 301<\/h3>\n
There are three main groups of commands that are used when backing up DHCP server database information from CLI (all of which are associated with the “Netsh” command-line tool). I’ll list them and give a brief breakdown of each set of commands.<\/p>\n
NOTE:<\/em><\/span> \u00a0There is a lot<\/em><\/strong> of information online pertaining to each of these commands\/options! I’ve extensively researched them all and will provide my perspective on what I’ve found. For now, I’ll just list them along with a brief explanation of each, and I’ll provide more details and examples beginning with Step 2.3<\/a><\/strong>.<\/p>\n
1.3.1. “Backup” & “Restore”<\/h4>\n
These are the equivalent of the GUI commands for backup and restore (the GUI commands are covered in more detail in Step 2<\/a><\/strong>). Command syntax is as follows:<\/a><\/p>\n
netsh dhcp server backup <backup folder location><\/pre>\n
netsh dhcp server restore <backup folder location><\/pre>\n
1.3.2. “Export” & “Import”<\/h4>\n
This is the most widely used set of commands for backing up and restoring a DHCP server database, and it’s the “best practice” and commonly recommended method referenced by Microsoft. As you could likely expect, there can arise some confusion about the difference between “Backup & Restore” vs “Export & Import”. The key difference to be aware of is this: “Backup” & “Restore” can be used to backup & restore a DHCP server database from and to the same OS version, whereas “Export” & “Import” can be used for both backing up and restoring from and to the same server, as well as between different server versions.<\/p>\n
To re-iterate and clarify this, if you want to backup a Windows Server 2008 R2 database and restore it to either the same server or to a different Windows Server 2008 R2 installation, you can use “backup & restore” or<\/strong><\/em> \u00a0“export & import”. However, if you want to backup a Windows Server 2008 R2 database and restore it to a Windows Server 2012 R2 server installation, you’ll want to only<\/strong><\/em> use the “export” & “import” commands. Export\/Import will be covered in more detail in Step 3<\/a><\/strong>. Command syntax is as follows:<\/p>\n
netsh dhcp server export <backup folder location & filename> <scope info to export> (use \"all\" for ALL scope info, or specify specific scope(s))<\/pre>\n
<\/a><\/p>\n
netsh dhcp server import <backup folder location & filename> <scope info to import> (use \"all\" for ALL scope info, or specify specific scope(s))<\/pre>\n
1.3.3. “Dump” & “Exec”<\/h4>\n
The “dump” command is essentially used to export the configuration info of a server (not<\/strong><\/em> \u00a0the entire database), and it’s generally only used for advanced troubleshooting and\/or configuration scenarios. While you could use these commands to export\/import configuration info from one server to another (with the same OS version or different OS version), I personally would only recommend using it to make changes to the same server that the information was exported from (or at least to the same OS version if your primary DHCP server dies).<\/p>\n
Let me help clarify this some more: There are multiple scenarios where using dump and exec can be handy. One example is that you could manually create a template file (a simple .txt file with all of your DHCP configuration info) and then use exec to import that configuration info into one or more servers. This process can save some configuration and deployment time in a “multiple DHCP server deployment” scenario.<\/p>\n
Another example of where the dump command can be handy is if you’d like to make a change to a DHCP scope. For example, if you’d like to change the subnet mask of a scope, this can’t be done without deleting the scope and recreating it. However, if there are a lot of customizations in the scope (like reservations and scope options), it’s going to be a lot of extra work to recreate all of that information. But with the dump command, you can export the configuration info for that specific scope, make modifications, then safely delete the scope from the DHCP MMC, and finally re-import all of the updated configuration info using the exec command. Dump\/Exec will be covered in more detail in Step 4<\/a><\/strong>. Command syntax is as follows:<\/p>\n
(Dump – two examples)<\/p>\n
netsh dhcp server scope <scopeaddress> dump > <backup folder location & filename><\/pre>\n
netsh dhcp server dump > <backup folder location & filename><\/pre>\n
(Exec)<\/p>\n
netsh exec <path location of dump file><\/pre>\n
NOTE 1:<\/em><\/span> \u00a0The single “>” after “dump” acts as a redirect which outputs all of the configuration info to a file.<\/p>\n
<\/a>NOTE 2:<\/em><\/span> \u00a0Before using the dump command, it’s recommended that you verify and reconcile any database inconsistencies (so your dump file is “clean”). I’ll cover “reconcile” and other cool tricks in more detail in Step 5<\/a><\/strong>.<\/p>\n
<\/a><\/p>\n
2. Backup & Restore (GUI & CLI)<\/h2>\n
In this first main section, I’ll detail the steps for doing a backup and restore from both the GUI and from the command line. Let’s start with the GUI steps first.<\/p>\n
2.1. Backup via GUI<\/h3>\n
The first backup option I’ll cover is a full backup from the GUI, via the DHCP management console. Again, as stated earlier in the article, this type of backup is ideal for either restoring to the same server and OS version, or to another server running the same OS version. On the server that you want to backup DHCP from, launch the DHCP MMC by navigating to it in the Administrative Tools menu. Refer to Figure 1 below:<\/p>\n
<\/a>Figure 1: DHCP MMC via Admin Tools menu<\/figcaption><\/figure>\n After the console window opens, your server should be listed. If not, right-click on “DHCP” and choose “Add Server”. A new window opens and your server should be listed in the box under “This authorized DHCP server:”. Select it and click “OK”. Refer to Figure 2a and 2b below:<\/p>\n
<\/a>Figure 2a: Add your DHCP server<\/figcaption><\/figure>\n <\/a>Figure 2b: Select the appropriate DHCP server<\/figcaption><\/figure>\n Once your server has been added to the list, right-click on it and choose “Backup”. A “Browse For Folder” window will open, and it will have the default backup folder location already selected (C:\\Windows\\System32\\dhcp\\backup); Click “OK”. Refer to Figure 3a and 3b below:<\/p>\n
<\/a>Figure 3a: Backup via the GUI<\/figcaption><\/figure>\n <\/a>Figure 3b: Selecting the default backup folder location<\/figcaption><\/figure>\n Unfortunately, the Windows OS does not give you any prompt or indication that the backup “completed successfully!”. However, you can open Windows Explorer and navigate to the backup folder and verify that the files have the appropriate date and timestamp. Refer to Figure 3c below:<\/p>\n
<\/a>Figure 3c: Backup complete (verify date\/timestamps)<\/figcaption><\/figure>\n <\/a>Remember to store a copy of this backup somewhere else besides the default backup location (as previously referenced in the Note in Step 1.1<\/a><\/strong>).<\/p>\n
2.2. Restore via GUI<\/h3>\n
Before doing the restore, I would recommend copying the folder from the saved backup (located on your storage server for instance; as referenced in step 1.1) to the desktop of the user profile of the admin account that you’re using to logon to the DHCP server. In my example, I’ve stored a copy of the backup in a folder named “dhcp”. Refer to Figure 4 below:<\/p>\n
<\/a>Figure 4: DHCP backup copied to desktop<\/figcaption><\/figure>\n NOTE:<\/em><\/span> \u00a0Before running the restore, if the old server will no longer be used to host DHCP services, you should either stop and disable the DHCP Server service, de-activate the scopes, or unauthorize the server (I would recommend this last option I mentioned). Refer to Figure 5a and 5b below:<\/p>\n
<\/a>Figure 5a: Unauthorize old DHPC server<\/figcaption><\/figure>\n <\/a>Figure 5b: Confirm unauthorize old DHPC server<\/figcaption><\/figure>\n NOTE:<\/em><\/span> \u00a0I would also recommend verifying the correct permissions on the backup folder that you copied to the desktop before<\/strong><\/em> \u00a0beginning the restore process (Refer to Figure 6f<\/a><\/strong> further down).<\/p>\n
Now it’s time to restore to the new server. To restore a backup, you would basically follow the same steps that were referenced in section 2.1, but choose “restore” instead of “backup”. As referenced in figure 2a and 2b, launch the DHCP MMC and make sure your new server is listed (if it’s not, add it).<\/p>\n
Once your server is available in the DHPC MMC, you should see some red down arrow emblems<\/em> \u00a0over the icons for IPv4 and IPv6 (indicating that the server is connected but not authorized). Authorize the new server by right-clicking on it and choosing “Authorize”. Refer to Figure 5c below:<\/p>\n
<\/a>Figure 5c: Authorize the new server<\/figcaption><\/figure>\n It will take a few moments for the server authorization to fully take effect. You can click “Action” from the menu and choose “Refresh” to update the status. When it’s successfully updated, you should see the emblems on the icons change from red down arrows<\/em> to green check marks<\/em> (indicating that the server is connected and active). Refer to Figure 5d below:<\/p>\n
<\/a>Figure 5d: Server successfully authorized<\/figcaption><\/figure>\n If the status doesn’t successfully update, open the Services MMC (via Administrative Tools) and restart the DHCP Server service (the far right toolbar button, or right-click the service and choose “Restart”). Once the service has been successfully restarted, it should look like this (Refer to Figure 5e below):<\/p>\n
<\/a>Figure 5e: DHCP Server service successfully restarted<\/figcaption><\/figure>\n Be sure to check the console again and verify that the server is authorized (refer back to Figure 5d). Once the server is successfully authorized, you can perform a restore. Right-click your server and choose “Restore…”. Refer to Figure 6a below:<\/p>\n
<\/a>Figure 6a: Restoring the DHCP backup<\/figcaption><\/figure>\n You will be prompted that the service must be restarted for the changes to take effect (this is normal); choose “Yes”. Refer to Figure 6b below:<\/p>\n
<\/a>Figure 6b: Prompt for restart of services<\/figcaption><\/figure>\n Once the backup has been successfully restored, you’ll see a confirmation message. Refer to Figure 6c below:<\/p>\n
<\/a>Figure 6c: Database successfully restored<\/figcaption><\/figure>\n NOTE:<\/em><\/span> \u00a0There are times when certain variables in the restore process are not quite right, which can cause various error messages. For instance, if the backup folder on the desktop does not have proper permissions configured, you could see messages like these (Refer to Figure 6d and 6e below):<\/p>\n
<\/a>Figure 6d: Insufficient permissions on the backup folder<\/figcaption><\/figure>\n <\/a>Figure 6e: Cannot find the file specified (permissions issue)<\/figcaption><\/figure>\n <\/a>Sometimes DHCP will prompt you that it can attempt to repair the permissions. But if that fails, or you need to verify\/set them manually, right-click on the backup folder on the desktop, choose “Properties”, click the “Security” tab, then click the “Edit” button. Verify that the user account you’re currently logged on with has “Allow” permissions for “Full control”. Refer to Figure 6f below:<\/p>\n
<\/a>Figure 6f: Verifying proper folder permissions<\/figcaption><\/figure>\n Try the restore again after you’ve set the correct permissions on the folder that you’re restoring from.<\/p>\n
If you ever get a service error message (Refer to Figure 6g below), you can wait a moment, restart the DHCP Server service, then try again:<\/p>\n
<\/a>Figure 6g: DHCP Server service error<\/figcaption><\/figure>\n <\/a>When the restore has completed successfully, you’ll be able to verify that all of the database information exists under “IPv4” (and “IPv6” if applicable) in your DHCP MMC.<\/p>\n
2.3. Backup via CLI<\/h3>\n
This is essentially the same procedure as in step 2.1, but done entirely from CLI using Netsh. The backup process via CLI is fast and simple compared to the GUI method (granted, neither method is difficult<\/em>, but the CLI method is much shorter in terms of steps involved, and more efficient in my opinion). This process can be done by remotely connecting to the DHCP server via a command prompt, but I prefer to directly logon to the server and run the commands from the server’s CLI.<\/p>\n
Open an admin command prompt by searching for “cmd” or “command prompt” via the Start menu, right-click on the search result, and choosing “Run as administrator”. Refer to Figure 7a below:<\/p>\n
<\/a>Figure 7a: Command Prompt via searching from Start menu<\/figcaption><\/figure>\n NOTE:<\/em><\/span> \u00a0If you’re prompted by UAC, click “Yes”. Refer to Figure 7b below:<\/p>\n
<\/a>Figure 7b: UAC prompt<\/figcaption><\/figure>\n Once the command prompt is open, doing a backup is as simple as typing the following command syntax:<\/p>\n
netsh dhcp server backup <backup folder location><\/pre>\n
In the example below, I backup the database to a folder named “dhcp” under “C:\\Users\\Admin\\Desktop\\” (Refer to Figure 8 below):<\/p>\n
<\/a>Figure 8: CLI backup<\/figcaption><\/figure>\n That’s it! Much faster via CLI!<\/p>\n
Before you proceed to the next section, if you’re no longer going to use your old server to provide DHCP services, unauthorize the server by typing the following command syntax:<\/p>\n
netsh dhcp delete server <ServerDNS> <ServerIP><\/pre>\n
- 5.2. Trick #2<\/a><\/dt>\n
- 4.2. Exec<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 3.2. Import<\/a><\/dt>\n<\/dl>\n<\/dd>\n
- 2.2. Restore via GUI<\/a><\/dt>\n
- 1.2. DHCP Backup Basics 201<\/a><\/dt>\n
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