As a solution to DHCP failure, the DHCP Failover was first introduced in Windows Server 2012 for the high availability of DHCP service. The DHCP high availability is a super important topic in DHCP Server setup and configuration. If the DHCP server fails to lease IP addresses to the clients, the whole network fails. Among other solutions to this issue, DHCP Failover is preferred and the most used. The way it works is that we have two DHCP servers working together. If one fails, we have the second one that provides the service. This article covers a step-by-step guide on how to configure DHCP Failover in Windows Server 2022. Before that, it covers a brief overview of the DHCP Failover configuration modes. This overview is required to distinguish between DHCP Failover configuration modes and which one to choose.

Before this configuration, you need to have DHCP installed and configured. You also need to have a DHCP scope. For those two topics, read the below articles.

• Install And Configure DHCP In Windows Server 2022 Using Server Manager.
• Create And Configure A DHCP Scope In Windows Server 2022.
• Install And Configure DHCP In Windows Server 2022 Using PowerShell.

DHCP Failover Configuration Modes

As mentioned above, two DHCP servers are involved with the DHCP Failover configuration. They work together to make the DHCP service highly available. To define how they should work together, we have two options: the Load Balance mode and the Hot Standby mode. We must go for the one that best suits our needs in accordance with the environment.

1. Load Balance Mode

Using the Load Balance mode, both the DHCP servers concurrently lease IP addresses to the clients. Also referred to it as Active/Active. That means both DHCP servers are active at the same time. They share the DHCP scope with one another, and each one leases IP addresses to a specific number of clients in the network. The number of clients each should serve is defined manually in percentage while we configure DHCP Failover. What happens when one fails? The other one takes the responsibility and leases IP addresses to all the clients.

2. Hot Standby Mode

Using this mode, only one of the DHCP servers is leasing IP addresses to the clients at a time. The primary one leases IPs to the clients. The secondary one is in the Standby mode and updates itself with a replication of the records from the primary server. The secondary one steps in and serves the clients only when the primary server crashes for any reason. This mode is also referred to as Active/Passive. That means only one is active at a time.

Step by Step DHCP Failover Configuration in Server 2022

Now that we are familiar with the DHCP Failover configuration modes, it is time to dive into the steps and practically configure the DHCP Failover on our DHCP Server.

1. Open DHCP Manager console. To do so, open the Run dialogue box using Windows Key + R keys on your keyboard and run dhcpmgmt.msc. You may also access the DHCP console by navigating through Server Manager > Tools > DHCP.

2. On the DHCP console, right-click on IPv4 under your domain and choose Configure Failover option from the list.

3. Remove the check for the Select all check box, and select the DHCP scope(s) from the list. Then, click on Next to continue.

4. Now, choose the partner server using the Partner Server box and Add Server button. You can type the name or IP address of the partner server in the Partner Server box or browse for it using the Add Server button. Click on the Next button once set.

5. The last step is to specify the DHCP Failover mode. You can use one of the Load Balance, or Hot Standby modes discussed earlier. You can set the properties for each one here on this page. Remove the Check for Enable Message Authentication check box if you do not use this authentication. Or, set it if you use it. Then, click on Next. Click on Finish on the next window and close the window using the Close button.

That is all the steps we require to Configure DHCP Failover on Windows Server 2022. Just five easy steps to accomplish it. If you switch to the partner server and go to the DHCP console, you will notice the DHCP scope(s) from your primary DHCP Server are replicated into it. Let’s verify it in a separate section.

Verify DHCP Failover Configuration

To verify if the DHCP Failover configuration works correctly, we have to check the partner server and see if the DHCP scope(s) that we chose are replicated. We have two ways to access the partner server’s DHCP console. One is to go to that server and navigate all the way to the DHCP Manager console. The second way is to access it remotely from the DHCP console. Let’s access it remotely and verify our DHCP Failover configuration through the steps below.

1. On the DHCP console, right-click on DHCP at the top and select Add Server option.

2. On the Add Server screen, select the target DHCP Server to access it. If the target DHCP Server is not already in the list, use the first option and the Browse button to find it. When you added the target server, click on OK.

3. Now that the Partner DHCP Server is added to the console, expand it, and you can see that the scope(s) that you chose in the DHCP Failover configuration are replicated and are present in both the servers.

4. One more thing. If you right-click on the DHCP scope(s) configured in DHCP Failover, you will notice the options to Deconfigure Failover, Replicate Scope, and Replicate Relationship.

By observing the replicated scope(s) and deconfiguration options for Failover, we can verify that our DHCP Failover configuration is correctly configured.

Conclusion

In a step by step approach, we covered how to configure a DHCP Failover in Windows Server 2022. We started with an overview of DHCP Failover configuration modes’ concepts. Then, we walked through the steps to practically configure the DHCP Failover. Finally, we remotely accessed our partner DHCP Server and verified the DHCP Failover configuration on it.

As always, I hope this article could be helpful to you. And, if there is any further question and thoughts you might want to share, let us know in the comment section.

The post How to Configure DHCP Failover in Windows Server 2022? appeared first on TECHNIG.

Dynamic Host Configuration Protocol (DHCP) is a handy protocol that automatically assigns IP addresses to clients in a network. It is one of the most popular and most used protocols in networking. DHCP plays a vitally important role in almost any enterprise of any size. We make use of this protocol in any network environment where we are dealing with assigning IP addresses to devices. As an example, it is present in a home router as well as in a large enterprise with thousands of devices connected to the network. One of the basic and fundamental topics regarding DHCP is its installation and configuration in an environment. And that is what this article covers in detail. Since Windows Server 2022 is the latest and most powerful Server OS, this article covers how to install and configure DHCP in Windows Server 2022 using Server Manager.

Installing DHCP Using Server Manager

Using Server Manager is an easy and user-friendly method to install DHCP on Windows Server 2022. This article explains the process in a step-by-step approach.

• Open Server Manager from the Start Menu.

• On the Server Manager console, click on Manage and choose Add Roles and Features. Then on the first wizard, click on Next.

• On the Installation Type, check out the first option as shown in the below picture, and then click on Next.

• Choose the server on which you want to install DHCP from the Server Pool section, and click on Next.

• Click on DHCP Server from the Roles list. Click on Add Features on the new window that pops up. Finally, click on Next.

• Just click on the Next button on both the Features and DHCP Server sections.
• On the Confirmation window, check out the Restart the destination server automatically if required and click on Install, afterwards. Wait a while until the DHCP role installation completes.

Once the last step gets completed, we are all done with the DHCP installation. However, we still need to perform the DHCP post-installation configurations like adding security groups and authorizing DHCP to the Active Directory Domain Services.

DHCP Post-Installation Configurations on Windows Server 2022

DHCP post-installation configuration on Windows Server 2022 is a brief and simple process. Particularly, we do two things: the first is adding DHCP security groups, and the second is DHCP authorization. They are, in fact, in continue to the DHCP installation. The followings are the steps.

• Right after the DHCP installation completes, we will see the blued Complete DHCP configuration text. See the picture below. This linked text takes us to the post-configuration wizard. We can close this window and still go to the post-configuration using the notification flag on the Server Manager. Both take us to the same window.

• Read the description on the first section of the DHCP post-installation wizard, and click on Next.

• In the Authorization section, specify your credentials to authorize DHCP in active directory domain services. You can put it as default, or specify manually using Specify button at the second option. Once done, click on the Commit button.

• Click on the Close button in the Summary section when the DHCP authorization completes.

That is it! As easy as the above steps, we can install and configure DHCP in Windows Server 2022. First, we must add DHCP roles and features. The second step is to perform the post-installation configuration for DHCP capability.

I hope this article gives you a helpful answer to your questions. If there are any further queries, share us in the comment section.

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Configure DHCP on Cisco Router. Last week we published a topic about installation and configuration of DHCP Server in Windows Server 2012 R2. We have introduced the DHCP Server “Install and Configure DHCP Server on Windows Server 2012 R2” and told the necessary services and network protocols requirement if you don’t know the basic of DHCP Server? you must read the article first.

Create and Configure a CCNA Lab within Cisco Packet Tracer.

Download the DHCP configuration in Cisco router lab of packet tracer from the end of this post or try to create your own network lab with two routers and their LAN networks and then configure it with the following step by step guide.

Configure the Router 1 with below IP address and initial configuration. I assume you know and understand the basic router and Switch configuration clearly. So no need to explain the functions of the basic router and switch commands line.

Router>enable
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.

Router(config)#hostname R1
R1(config)#interface serial 0/0/0
R1(config-if)#ip address 10.10.10.1 255.255.255.252
R1(config-if)#no shutdown

R1(config-if)#clock rate 64000
R1(config-if)#

For Router 2, configure the same interface serial 0/0/0 and FastEthernet 0/0 with the following commands.

Router>enable
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#hostname R2
R2(config)#interface serial 0/0/0
R2(config-if)#ip address 10.10.10.2 255.255.255.252
R2(config-if)#no shutdown

R2(config-if)#

R2(config)#interface fastEthernet 0/0
R2(config-if)#ip address 192.168.10.1 255.255.255.0
R2(config-if)#no shutdown

Configure DHCP on Cisco Router Using Packet Tracer

Let’s configure Router 2 as DHCP Server and set the clients to get their IP address from DHCP Server in Cisco Router.

In the R2 while you are in the config mode, type the command ‘IP DHCP excluded-address 192.168.10.1 192.168.10.20‘ and then press enter. This command ‘ip dhcp excluded-address’ will create an exclusive range of IP addresses which reserved for Network Servers and DHCP Server will not assign them to clients.

The ‘ip dhcp pool‘ command creates a pool for a network. You can create many pools on a router for all Local area network that connected to the router.

R2>enable
R2#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#ip dhcp excluded-address 192.168.10.1 192.168.10.20
R2(config)#ip dhcp pool Technig_Clients
R2(dhcp-config)#
R2(dhcp-config)#network 192.168.10.0 255.255.255.0
R2(dhcp-config)#default-router 192.168.10.1
R2(dhcp-config)#dns-server 192.168.10.100
R2(dhcp-config)#

Now go to client setting and set the IP Configuration to DHCP and see the client get a new IP address from DHCP Server.

So that’s it, configure DHCP on Cisco router within a minute! Simple and easy.

DHCP Relay on Cisco Router

Remember some DHCP options (DHCP Relay Agent) when you need to provide IP addresses from a DCHP server to clients that are outside of your network or are not in the same Local Area Network. You must use the ‘ip helper-address‘ to forward the DHCP client requests to the remote host.

Configure the R1 to relay the DHCP client request. It does not work without routing. So configure Routers with static or dynamic routing. Here I’m testing with RIP.

R1>enable
R1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#interface fastEthernet 0/0
R1(config-if)#ip helper-address 10.10.10.2
R1(config-if)#exit

R1(config)#router rip
R1(config-router)#network 10.10.10.0
R1(config-router)#network 192.168.30.0
R1(config-router)#exit

Go to the client IP configuration setting and see the forwarded request by DHCP Server.

Hope you learn the configuration of the DHCP Server on the Cisco Router and Download the DHCP on Cisco Router Packet Tracer.

Related Search: 

Configure DHCP on cisco router interface
Configure DHCP on cisco router in packet tracer
What is DHCP pool
Configure DHCP on cisco switch 2960
How to configure DHCP pool on cisco switch
IP DHCP excluded-address
Cisco DHCP lease command
IP DHCP server

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