DHCP Failover KB ID 0001488

Problem

Applicable to: Server 2012/2016/2019/2022

Even though we have had this functionality for a while, I’m still seeing people deploy DHCP scopes (split 80/20) across two servers?

You can deploy multiple DHCP servers to serve the SAME DHCP scopes, in either load balanced, or hot standby deployment.

Solution: DHCP Failover

I’m assuming you already have one DHCP server setup and, with a working DHCP scope. On the new server, install the DHCP server role;

[box]Install-WindowsFeature DHCP -IncludeManagementTools[/box]

You normally have to go to Server Manager and run the configuration wizard, but as were are already in PowerShell lets do that here 🙂 (That’s three commands if the last one wraps!)

[box]

netsh dhcp add securitygroups

Add-DhcpServerInDC -DnsName pnl-mgmt.pnl.com -IPAddress 192.168.100.3

Set-ItemProperty –Path registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ServerManager\Roles\12 –Name ConfigurationState –Value 2

[/box]

On the original, (already working,) DHCP server, right click the scope you want to replicate > Configure Failover. Note: If you have multiple scopes you can right click at the IPv4 or IPv6 level, and run the same wizard to replicate multiple scopes at once).

Next.

Browse to, and select the target (new DHCP server) > Next.

Select Load Balancing or Hot Standby (as required) > Enter a shared secret password > Next.

Review the Settings and click Finish.

Hopefully you should see the following.

Configure DHCP Failover via PowerShell

To do the same from PowerShell.

PowerShell DHCP Load Balancing

Note: Where DC-01 is the source DHCP server and PNL-MGMT is the new one.

[box]Add-DhcpServerv4Failover –ComputerName “DC-01” –PartnerServer “PNL-MGMT” –Name “DHCP_DC01_PNLMGMT_LoadBalance” –LoadBalancePercent 50 -MaxClientLeadTime 1:00:00 -StateSwitchInterval 00:45:00 -ScopeId 192.168.200.0 -SharedSecret “Password123“[/box]

PowerShell DHCP Hot Standby

Note: Where DC-01 is the source DHCP server and PNL-MGMT is the new one.

[box]Add-DhcpServerv4Failover -ComputerName “DC-01” –PartnerServer “PNL-MGMT” -Name “DHCP_DC01_PNLMGMT_Hot_standby” -ServerRole Active -ReservePercent 10 -MaxClientLeadTime 1:00:00 -StateSwitchInterval 00:45:00 -ScopeId 192.168.200.0 -SharedSecret “Password123“[/box]

Related Articles, References, Credits, or External Links

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