How Does DHCP Failover Benefit Your Business?

Highlights from the Article

  • Every organization needs to include DHCP in its network. Otherwise, clients won’t be able to obtain IP addresses and information such as DNS servers.
  • DHCP failover helps enterprises minimize downtime and its implications by ensuring high availability on Windows Servers used to maintain business operations. The service is built into the Windows server operating system.
  • The only ways enterprises can configure DHCP failovers are load balance and Ho Standby. You can switch between the two, but only one mode can be active at the time of use.
  • DHCP servers configured for failover share scope information which includes all active leases. The configuration cannot include more than two DHCP servers.
  • Network downtime can be costly to a business. The implications are lost revenue, productivity, and the cost associated with fixing the problem.

The internet has become integral for daily business operations and communications, so network performance and high availability are necessary for any enterprise. Outages and problems within the network cause downtime, which gets in the way of productivity and may be costly. Additionally, if your business regularly experiences network downtime, it can dent your reputation among partners and customers. Any business whose strategy relies on the performance of its networks must take necessary measures to implement infrastructure and systems that will ensure its networks run with minimal disruptions.

Why is DHCP Failover so Important?

The Dynamic Host Configuration Protocol (DHCP) is a network management practice that automates configuring devices on IP networks. It resides inside the DHCP server, which assigns IP addresses to devices connected to your corporate network. The server makes the work of network administrators easier by automating the configuration of IP addresses across the entire network and managing the addresses as the devices connect or disconnect. Depending on the size of your organization, a DHCP server can be a router or a single dedicated computer.

Failure of the DHCP server means it cannot distribute IP addresses, and eventually, your business devices will not be able to connect to the internet. Since failures are often unforeseen, the best way to prepare is to create failover capability in the DHCP servers. This will protect the servers during a failure ensuring that you carry on your operations with little to no disruption by enabling redundancy and load balancing of DHCP services.

What is DHCP Failover?

In a communication network, failover transfers tasks from an unavailable component to a similar redundant component. The goal is usually to avoid disruptions, especially when the components are at the center of operations.

A DHCP failover works the same way, with the components of focus being DHCP Windows Servers 2012. It allows the configuration of two DHCP servers such that they both can lease IP addresses from the same address pool without risk of duplication. The failover ensures DHCP high availability by sharing all scope information, including active leases between the two configured servers. When either of the DHCP servers is unavailable, the other can assume responsibility for the clients for load balancing and redundancy purposes. Servers sharing a failover-enabled DHCP scope are called failover partners.

How Does DHCP Failover Work?

DHCP servers configured for failover manage the same pool of addresses. Therefore, they can share the load of assigning leases for that particular pool and providing backup for one another in the event of a network outage. Usually, failover partnerships are configured per pool so one DHCP server can have several active partnerships with different peers. There are several configuration options within the DHCP failover. An enterprise may configure failover on all scopes within a DHCP server or just a few selected scopes.

You can also use the same DHCP failover setting for several scopes by including them in the same failover relationship. However, remember that a failover relationship can only be between two DHCP servers. Still, a single server can have multiple failover relationships as long as it is with a different DHCP server.

Changes to a failover-enabled scope must be replicated to the partner server to ensure the scopes on both DHCP servers are synchronized. During replication, scope settings from the DHCP server where replication is initiated are copied to the partner server, overwriting any existing settings. Therefore, you must always initiate replication from the server with the DHCP scope settings you want to use.

Choosing Your DHCP Failover Option

There are two ways to configure DHCP failover: Load balance and Hot Standby.

Load Balance 

Load balance sharing mode is most suitable for DHCP servers operating within a centralized location. In this failover option, each server gets to assign DHCP information to clients based on your preferred load ratio. Therefore both servers will be active simultaneously, but when one loses contact, the failover partner will take over, granting leases to all DHCP clients but only within the designated capacity. Usually, the servers will split the addresses scope 50:50 by default, but you can set it to whichever works best for you.

Hot Standby

The hot standby mode configuration has one server in the failover relationship on standby while the other is solely responsible for issuing IP addresses and configuration information to clients. The server on standby will only come into play when the primary server is unavailable. Enterprises with more than one branch can benefit from this configuration by the primary server in a local branch office and the standby DHCP server at the regional or main office.

Concluding Remarks

DHCP failover gives your organization comfort in knowing that you can rely on your DHCP servers without interruptions. It seems like an unnecessary financial load, but the safety and convenience it provides are worth it. While it may not completely stop system failure, at the very least, it reduces complete shutdown, which can have severe consequences on a business. DHCP failover is an essential component of any business disaster recovery plan, and when correctly configured, there will be seamless and significant protection against service disruption.

To learn more about your enterprise can make the most of DHCP failover or any other IT solutions, contact On-Site Computer today. We offer managed IT services to small to mid-sized companies in Minnesota and surrounding areas.

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Mike Bowe | Published on November 28, 2022

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