Last updated on Feb 12, 2025

How do you update or migrate DHCP failover settings and partners without disrupting service?

DHCP failover is a feature that allows two DHCP servers to share the same scope and provide redundancy and load balancing for DHCP clients. However, sometimes you may need to update or migrate your DHCP failover settings and partners, for example, to change the mode, modify the IP addresses, or move to a different server. How do you do this without disrupting service and causing errors or conflicts? In this article, we will show you how to use PowerShell commands and Windows Server tools to update or migrate DHCP failover safely and smoothly.

1 Backup your configuration

Before you make any changes to your DHCP failover settings and partners, you should always backup your configuration and database. This way, you can restore them in case something goes wrong or you need to revert to the previous state. You can use the Export-DhcpServer and Import-DhcpServer cmdlets in PowerShell to backup and restore your DHCP configuration and scopes. You can also use the Backup-DhcpServer and Restore-DhcpServer cmdlets to backup and restore your DHCP database.

Add your perspective

✅ Dr. Marc Arnaert NIST/CIS/EIC/SANS

GRC - NIST/ IEC 27001 - Compliance, Architecture, Vulnerability Auditor
(edited)
Report contribution
Powershell commande pour le Backup : Export-DhcpServer -File c:\temp\dhcp-backup\dc01.xml -Leases -Force -ComputerName dc01.local Powershell commande pour la restauration : Import-DhcpServer -File c:\temp\dhcp-backup\dc01.xml -BackupPath c:\temp\dhcp-backup\ -Leases -ScopeOverwrite -Force -ComputerName dc01.local -Verbose

Like
Craig M.

Senior Cloud Solution Architect at Microsoft
Report contribution
I agree but it should be noted that this is for Microsoft/Windows DHCP servers. These steps won’t apply to Unix based DHCP solutions.

Like
Erwin Derksen

Co-Founder / Sr. Architect / Public Speaker / Microsoft 365 / Azure / Security / Active Directory / Big fan of Simplicity
Report contribution
PLEASE be aware that the export features DO NOT export all SERVER OPTIONS. A secure way of migrating ALL settings completely is by creating a backup of the database (made in c:\windows\system32\dhcp\backup) and copy that to the new DHCP server. I have seen quite some cases where customers followed the Microsoft documentation, resulting in missing options, which can cause disruptions. So make sure you always have a recent copy of your DHCP Database.

Like

2 Remove the failover relationship

The next step is to remove the existing failover relationship between the two DHCP servers. This will stop the synchronization and replication of leases and settings between them. You can use the Remove-DhcpServerv4Failover cmdlet in PowerShell to remove the failover relationship. You need to specify the name of the primary server and the name or IP address of the secondary server. You can also use the DHCP console in Windows Server to delete the failover relationship from the scope properties.

Add your perspective

Erwin Derksen

Co-Founder / Sr. Architect / Public Speaker / Microsoft 365 / Azure / Security / Active Directory / Big fan of Simplicity
Report contribution
I have the experience that restoring DHCP databases on new servers works like a charm, BUT the failover relation doesn't seem to work always for 100%. For example, had the experience that all looked fine, all changes repliacted etc. Untill i created a new scope, when i tried to replicate that as well using the existing relation it failed. After removing and re-creating all worked well, so i would reccomend doing that in all cased just to be sure in a production environment. Also Powershell can report a different status then the GUI, so i reccoment recreating as it takes little effort.

Like

3 Update or migrate your settings and partners

Now that you have removed the failover relationship, you can update or migrate your DHCP failover settings and partners as needed. For example, you can change the failover mode from load balance to hot standby, or vice versa, by using the Set-DhcpServerv4Failover cmdlet in PowerShell. You can also modify the IP addresses of the primary and secondary servers, or change the partner server to a different one, by using the same cmdlet. You can also use the DHCP console in Windows Server to edit the failover properties from the scope properties.

Add your perspective

4 Reconfigure the failover relationship

The final step is to reconfigure the failover relationship between the two DHCP servers. This will resume the synchronization and replication of leases and settings between them. You can use the Add-DhcpServerv4Failover cmdlet in PowerShell to create a new failover relationship. You need to specify the name of the primary server, the name or IP address of the secondary server, the failover mode, and other optional parameters. You can also use the DHCP console in Windows Server to configure the failover from the scope properties.

Add your perspective

5 Test and verify your configuration

After you have reconfigured the failover relationship, you should test and verify that your DHCP failover is working as expected. You can use the Get-DhcpServerv4Failover cmdlet in PowerShell to check the status and details of the failover relationship. You can also use the DHCP console in Windows Server to view the failover statistics and events from the scope properties. You should also check that your DHCP clients are able to obtain and renew leases from either server without issues or delays.

Add your perspective

6 Troubleshoot any errors or conflicts

If you encounter any errors or conflicts during or after updating or migrating your DHCP failover settings and partners, you should troubleshoot them as soon as possible. Some common errors or conflicts include mismatched scope options, duplicate IP addresses, communication failures, or state transitions. You can use the Resolve-DhcpServerv4IPConflict cmdlet in PowerShell to resolve any IP conflicts between the two DHCP servers. You can also use the Force-DhcpServerv4FailoverReplication cmdlet in PowerShell to force a replication of leases and settings between them. You can also use the DHCP console in Windows Server to resolve any errors or conflicts from the scope properties.

Add your perspective

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

Add your perspective

Craig M.

Senior Cloud Solution Architect at Microsoft
Report contribution
Make sure to coordinate with your networking teams to verify if there are switches or routers with DHCP helper addresses defined that may need to be updated.

Like
Erwin Derksen

Co-Founder / Sr. Architect / Public Speaker / Microsoft 365 / Azure / Security / Active Directory / Big fan of Simplicity
Report contribution
Make sure you make a copy of the c:\windows\system32\dhcp\backup folder to make sure you can recovery ALL settings including server options that otherwise might get lost when migrating to another server.

Like

Dynamic Host Configuration Protocol (DHCP)

How do you update or migrate DHCP failover settings and partners without disrupting service?

1

2

3

4

5

6

7

1 Backup your configuration

2 Remove the failover relationship

3 Update or migrate your settings and partners

4 Reconfigure the failover relationship

5 Test and verify your configuration

6 Troubleshoot any errors or conflicts

7 Here’s what else to consider

Dynamic Host Configuration Protocol (DHCP)

Rate this article

Thanks for your feedback

More articles on Dynamic Host Configuration Protocol (DHCP)

More relevant reading