DHCP ensures network accessibilty, safety

Posted by B. Hale

If you're like most people, you don't think much about what a Dynamic Host Configuration Protocol is and how and why it keeps your network-connected devices available to authorized users and clients.

Every device on a TCP/IP-based computer network must have a unique IP address in order to gain access to the network and its resources. Simply put, without DHCP, IP addresses for new computers or for computers that are moved from one subnet on your network must be configured manually. IP addresses for computers that are taken off a network msut also be manually reclaimed without the protocol

So, what's a DHCP anyway?

The DHCP is utilized on every IP network. Controlled by a server that distributes IP addresses and other network configuration parameters necessary for inhterfaces and services, a DHCP allows computers to request IP addresses and networking parameters automatically. That reduces the need for either a network administer or user to manually configure settings.

A router or residential gateway can be set up to act as a DHCP server. If you do not have a server, each computer or other device (such as a printer) will have to be manually given a unique IP address.

What does it do?

The protocol manages IP settings for each device on a computer network by automatically assigning IP addresses to each device and operates based on the client-server model. When an electronic device is connected to a network, the DHCP sends out what's known as a broadcast query asking for an IP address for the device by managing a pool of IP addresses and information about default parameters.

Operations fall into four parts known as server discovery, an Internet Protocol lease offer, an Internet Protocol lease request and an Internet Protocol lease acknowledgment.


The protocol ensures the reliability of computer networks in several ways, including periodic lease renewals, rebinding to a backup server and failover which occurs when the lease expires and the client must stop using the IP address.

In short, it provides reliable IP address centralization and configuration to computer networks.


The protocol is vulnerable to a variety of attacks by hackers because many do not include any mechanism for authentication, meaning that unauthorized servers can provide false information to clients and may allow unauthorized users access to your computer network.

However, these problems can be mitigated when network operators attach tags to messages when they arrive on the network operator's trusted network. Known as Option 82, the tag is used as an authorization to control the client's access to network resources.