What Is DHCP?

DHCP stands for dynamic host configuration protocol and is a network protocol used to automate the configuration of devices on internet protocol (IP) networks. DHCP is likely working in your home and connecting your devices, often without you realising it. It assigns private IP addresses to computers, smartphones, Wi-Fi devices, and gadgets, which all use a single network, such as a router, that contains the public IP address. On a wider scope, it connects any device to any IP network, whether a local area network (LAN) or a wide area network (WAN).

Devices must connect to a public IP address to send information to each device. As devices use private IP addresses, these do not stay the same and are assigned at each use time. They collectively dip into a pool of IP addresses that a device uses and then put back when you stop using the device. It would take a long time to configure these manually, so DHCP does this effortlessly, most of the time without you giving it any thought. 

DHCP components

DHCP consists of three components: the DHCP server, DHCP client, and DHCP relay agents. Take a closer look at each one and what they are responsible for.

DHCP server

The server issues the IP addresses and can tell the clients on its network apart. The DHCP server allows network administrators to assign client rules, such as applying a subnet mask and assigning a remote host to store lease information.

DHCP client

Clients are devices that connect to a network, such as phones, computers, printers, and servers. The communication between the client and server follows a process called the DHCP handshake:

1. Discover: The client who wants to connect to the internet sends a message (packet) to DHCP servers.

2. Offer: The DHCP server receives the message and offers all the private IP addresses.

3. Request: The client selects an IP address and sends a message to other clients on the network to ensure it is not already used.

4. Acknowledge: The DHCP server acknowledges the client’s request and sends all the relevant information needed to connect to the server. 

DHCP relay agents

Relay agents transport requests between the client and the server. They are not necessary on a small network with limited devices, but they're effective in larger networks, especially ones using remote servers.

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DHCP, or dynamic host configuration protocol, automatically assigns IP addresses to devices on a network, freeing users from manually setting them up. DHCP uses a pool of addresses, offering one to a requesting device and acknowledging it for use. In larger networks, relay agents help manage communication between clients and servers.

Understanding protocols like DHCP and other network processes is highly relevant to a career in IT support. If you have this knowledge and experience or are just starting, consider adding a Professional Certificate to your resume. The Google IT Support Professional Certificate on Coursera can help you learn the fundamentals of IT support and upgrade your current skills. With this Professional Certificate, you can aim to be job-ready in IT support in six months or less.