In this article, I will explain what a DHCP server is and how DHCP works to make managing IP addresses easier on the Internet and private networks.
A DHCP Server is a network device that automatically assigns IP addresses and other network settings to endpoints. DHCP servers have simplified networking since the early 1990s, providing IT admins with the ability to automate IP address assignment.
The world of manually assigning static IP addresses to network devices is a thing of the past. And DHCP servers continue to support this process as the Internet moves from IPv4 to IPv6. How does it all work? Let’s find out!
DHCP, or Dynamic Host Configuration Protocol, is a client and a server protocol that automatically provides an Internet protocol (IP) address and other related information such as the subnet mask and the default gateway to network endpoints.
A DHCP Server is the device that provides this solution. Either as a physical or a virtual server, it can be a network appliance. Without a DHCP server, network administrators would need to manually set up every client that joins the network, which would be very time consuming, particularly in large networks.
DHCP runs at the application layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) stack to dynamically assign IP addresses to Dynamic Host Configuration Protocol clients and to allocate TCP/IP configuration information to those Dynamic Host Configuration Protocol clients.
When a Dynamic Host Configuration Protocol server receives the message from the endpoint, it also broadcasts a DHCP offer message over the Ethernet network, informing the endpoint that it is available.
DHCP is made up of some key components:
Table 1 – Components of DHCP
|DHCP Servers||A server or a router that holds the network information|
|DHCP Client||An endpoint, whether it’s an Apple iPhone, Windows 11 PC, hard-wired camera into the network, all endpoints require the configuration information received from the server|
|DHCP Relay Agent||DHCP servers provide requests for the network segment which it looks after. DHCP requests can’t span across different local area networks (LAN), a Relay Agent allows for the DHCP server to provide for multiple LAN’s and will forward the requests to the servers|
|IP Address Pools||Lists of all the IP addresses that can be assigned to the endpoints|
|Lease Times||The time in which an IP address can be allocated to an endpoint is done through the lease time. This prevents endpoints from holding onto the IP address indefinitely. Once the lease is up, the device can then renegotiate with the server to ensure the IP address is either retained or moved to another suitable IP address|
|Subnet Mask||Informs the endpoint what network it is currently presented with. Networks are segmented using subnet masks|
|Gateway Addresses||Tells the endpoint where to find the network gateway to connect to the Internet or how to connect to another adjoining network|
One of the key advantages is you no longer need to worry about duplicate/multiple endpoints using the same IP addresses. We are human, we make mistakes, DHCP servers take this mismatch away from us.
The deployment of DHCP is meant to be easier, far easier than it was back in 1993! We can implement the automatic assignment of IP addresses, meaning that it’s vastly more accurate.
The manual configuration of subnet masks, gateways, IP addresses on a static method is no longer required and network engineers and administrators can move their interests into something much more worthwhile. The configuration is obtained the same by all users whether the endpoint is static or mobile, whether they are attached for minutes or months. The network configuration is obtained automatically when devices change their network.
Other benefits of DHCP Servers include:
DHCP isn’t perfect, and here are some of the DHCP issues you might encounter:
DHCP is a way of life for the world of IT administration. DHCP will be with us for as long as we continue to use IPv4, and we are likely to see it within IPv6 too. There is no getting away from the use of DHCP for large network administrators.
Microsoft continues to provide exams such as Networking Fundamentals and will continue to create new exams for as long as we require computers to be networked together. Windows Server can also be set up as a DHCP Server. In addition, sources such as CompTIA also provide accreditation in the Network+ exam provide a vendor-agnostic approach to further education and accreditation. Good Luck on your path ahead!