Manage DHCP failover relationships in Windows Server

To configure a failover relationship using PowerShell, complete the following steps:

1. On the Windows desktop, select the Start button and type any part of the name Windows PowerShell.

2. Right-click Windows PowerShell and select Run as Administrator.

3. Use the PowerShell cmdlet Add-DhcpServerv4Failover to add an IPv4 failover relationship on the DHCP server service. Run the following command to create a load balance failover relationship:

Add-DhcpServerv4Failover -ComputerName "dhcp1.contoso.com" -Name "dc1-dhcp1" -PartnerServer "dhcp2.contoso.com" -ScopeId 10.10.10.0,10.20.20.0 -SharedSecret "sEcReT"

This command creates a load balance failover relationship between dhcp1.contoso.com and dhcp2.contoso.com. The failover has scopes 10.10.10.0, and 10.20.20.0 present on dhcp1.contoso.com. These scopes are created on the partner DHCP server service that runs on the computer named dhcp2.contoso.com as part of the failover relationship creation. Message authentication is enabled for the server-to-server message exchange with the specified shared secret.

To create a hot standby failover relationship, use the command:

Add-DhcpServerv4Failover -ComputerName "dhcp1.contoso.com" -Name "dc1-dhcp1" -PartnerServer "dhcp2.contoso.com" -ServerRole Standby -ScopeId 10.10.10.0,10.20.20.0

dhcpserver.contoso.com is the standby DHCP server service, and dhcpserver2.contoso.com is the active DHCP server service in the failover relationship.

To configure a failover relationship using the DHCP console, complete the following steps:

1. Open Server Manager if it's not already open.

2. Select Tools, then DHCP.

3. In the DHCP console, select your server, and expand it so you see IPv4.

4. Right-click on IPv4, and select Configure Failover....

   

5. The Configure Failover wizard opens. A list of available DHCP scopes displays. You can choose multiple scopes if you like. In this example, a single DHCP scope is configured using a new failover relationship.

   

6. Select Next, and then on the Specify the partner server to use for failover page, for Partner Server type the name, or IP address of the failover partner DHCP server. You can also use the drop-down list to choose from a list of authorized DHCP servers in the ___domain.

7. To reuse an existing DHCP failover relationship, select Next. Alternatively, to create a new DHCP failover relationship, clear the Reuse existing failover relationships… checkbox, and then select Next.

8. On the Create a new failover relationship page, type a name for the failover relationship next to Relationship Name, or accept the default name.

   For Mode, select either Load balance, or Hot standby. Complete the configuration details for your selected mode.

   By default, the Enable Message Authentication checkbox is enabled. Clear this checkbox if you don't wish to use a shared secret. Otherwise, type a shared secret next to Shared Secret. By default, load balancing is set to 50% for both the local server and the partner server.

   

9. Select Next, select Finish, verify that the status of all the tasks are successful, and then select Close.

In the previous examples, a new failover relationship named dc1-dhcp1 is established between dhcp1.contoso.com and dhcp2.contoso.com. To use a 50-50 load balancing percentage for the DHCP scope with ID 192.168.10.0.

To view failover relationships on a DHCP server, you can use the cmdlet Get-DhcpServerv4Failover in an elevated Windows PowerShell prompt.

1. On the Windows desktop, select the Start button and type any part of the name Windows PowerShell.

2. Right-click Windows PowerShell and select Run as Administrator.

3. Run the following command:

Get-DhcpServerv4Failover

    Name                : dc1.contoso.com-192.168.0.254
    PartnerServer       : 192.168.0.254
    Mode                : HotStandby
    LoadBalancePercent  :
    ServerRole          : Active
    ReservePercent      : 5
    MaxClientLeadTime   : 01:00:00
    StateSwitchInterval :
    State               : Normal
    ScopeId             : {192.168.50.0, 192.168.0.0}
    AutoStateTransition : False
    EnableAuth          : False
    
    Name                : dhcp1-dc1 load balance
    PartnerServer       : dhcp1.contoso.com
    Mode                : LoadBalance
    LoadBalancePercent  : 50
    ServerRole          :
    ReservePercent      :
    MaxClientLeadTime   : 01:00:00
    StateSwitchInterval :
    State               : Normal
    ScopeId             :
    AutoStateTransition : False
    EnableAuth          : False

An advantage to using Windows PowerShell to view failover relationships is that you can view more properties of the DHCP failover relationship than you can see in the DHCP console.

To view failover relationships using the DHCP console, complete the following steps:

1. Open Server Manager if it's not already open.

2. Select Tools, then DHCP.

3. In the DHCP console, select your server, and expand it so you see IPv4.

4. Right-click on the scope name, and then select Properties, and then select the Failover tab.

   

To edit failover relationships on a DHCP server, you can use the cmdlet Set-DhcpServerv4Failover.

1. On the Windows desktop, select the Start button and type any part of the name Windows PowerShell.

2. Right-click Windows PowerShell and select Run as Administrator.

3. Run the following command:

Set-DhcpServerv4Failover –Name "dhcp1-dc1" –LoadBalancePercent 70

This command changes the failover relationship dhcp1-dc1 to take 70% of the client requests served by the DHCP server.

To edit failover relationships using the DHCP console, complete the following steps:

1. Open Server Manager if it's not already open.

2. Select Tools, then DHCP.

3. In the DHCP console, select your server, and expand it so you see IPv4.

4. Select Properties, and then select the Failover tab.

5. Choose a failover relationship, and then select Edit. A window opens where you can edit details about the selected failover relationship.

To edit failover relationships on a DHCP server, you can use the cmdlet Remove-DhcpServerv4Failover.

1. On the Windows desktop, select the Start button and type any part of the name Windows PowerShell.

2. Right-click Windows PowerShell and select Run as Administrator.

3. Run the following command:

Remove-DhcpServerv4Failover –Name dhcp1.contoso.com-dhcp2-dns1.contoso.com

To delete a failover relationship using the DHCP console, complete the following steps:

1. Open Server Manager if it's not already open.

2. Select Tools, then DHCP.

3. In the DHCP console, select your server, and expand it so you see IPv4.

4. Select Properties, and then select the Failover tab.

5. Highlight the relationship name on the Failover tab and then select Delete. You're prompted to confirm the deletion, and see if any scopes are currently associated with the failover relationship.

   

6. Select OK to confirm deletion of the failover relationship. Deleting a failover relationship with DHCP scopes associated with it removes those scopes from the partner DHCP server. The scopes remain on the DHCP server where the failover relationship was deleted.