What is a DHCP Client?
Introduction
A DHCP client is a device that utilizes the Dynamic Host Configuration Protocol to obtain an IP address. The internet protocol specifies how devices on computer networks should communicate with each other, and defines port numbers for services such as FTP, HTTP, SSH, HTTPS, etc. A DHCP server will allocate IP addresses automatically to clients in order for them to connect to the network. A DHCP client will renew its IP address lease, and may also release it when the device is shutting down or initiating a sleep state. It can also notify the server that it has failed and needs another IP address to be allocated for it.
DHCP differs from a fixed IP address in that it is dynamic – a device can have a DHCP client configured, and then the IP address may change. For example, a switch could be configured with an IP address statically (quite common) but if someone plugs another switch into this one, the new device will not have a fixed IP address. For this reason, a device can have a different IP address every time it connects to the network.
In a DHCP transaction, a device will broadcast to the network asking if any other device has been allocated an IP address beginning with specific numbers. This is known as a DHCP Discover message.
What is a DHCP Client?
A DHCP client is a device that sends a request to a DHCP server for an IP address. The address is typically represented as four numbers separated by periods. These numbers are the number of the network, the number of the specific node on the network, and the number of the subnet on the node it is sitting on, and finally an individual or organizational identifier.
A DHCP client typically requests an IP address from a DHCP server in order to get onto a computer network. Continually asking for an IP address can be a sign of a lack of reliability in the device’s own networking hardware. This is because the device has to keep asking for a new IP address over and over again as it moves from one wireless access point to another. While the device is using one wireless access point, that access point might be assigned an entirely different IP address by a DHCP server. In this case, the device must again ask for a new IP address. This is a common issue with wireless devices.
Why do I need to know about this?
It is an integral part of setting up your home network. You can use it to get a lease on an IP address and you’ll need the gateway and domain name servers addresses for your local internet service provider (ISP). It also gives you the local time zone and other information.
In the simplest terms, a DHCP client is a piece of software that runs on your computer. You can also have a broadband router with a built-in DHCP client. A DHCP client queries the DHCP server to get its address and information so it has everything it needs to operate on your network.
It works by taking advantage of the dynamic host configuration protocol (DHCP), which allows clients to automatically get their network settings when they need them. When you turn on your computer, it checks for the DHCP server in the area and requests an address from the list of offered addresses.
How does it work?
When you connect to the Internet, your computer should acquire an IP address from a Dynamic Host Configuration Protocol (DHCP) server. If it doesn’t, then the DHCP server will step in and offer you an address that’s currently not being used.
Now, computers can be configured to use DHCP automatically. Once the computer is connected to the network, it will ask for an IP address. If it is available on that network, then the DHCP server assigns one to the computer through a lease agreement for a certain amount of time (based on your configuration).
Now, if you want to access the Internet or a network, you need to know your IP address. It’s always good to have it just in case something happens. If the network you are using does not have a DHCP server enabled, then your computer will automatically acquire an address on its own.
However, if you do see that you are connected to a network without DHCP available, there is no need to worry. That means that the administrator of the network has set up static IP addresses for everyone who wants to access it.
How many types of DHCP Clients are there?
There are two types of DHCP Clients:
- The Address Request Client
- The Address Offer Client.
The Address Request client is a client that broadcasts the DHCP packet to the network. This type of client requests for an IP address from any DHCP server that’s available in the network. This type of client doesn’t have the capability to receive an offer from a specific DHCP server, so if there are no DHCP servers available, then this client will not get an IP address.
The Address Offer client is a client that broadcasts the DHCP packet to the network and waits for a DHCP server to offer it with an IP address. Unlike the Address Request client, this type of client can receive offers from multiple DHCP servers. If the client receives an offer from a specific DHCP server, it will accept the offer and activate its IP address.
Conclusion
A DHCP Client is a network device that asks for an IP address from a server on the local area network. The DHCP client will then get assigned to a defined range of IP addresses and can use these addresses in order to communicate with other devices on the LAN. A common example of this would be your home WiFi router or modem which may have settings configured by you manually, but also assigns itself automatically if it does not find any pre-configured information about how to do so. In general, most people don’t need to worry too much about what the DHCP client is because they are usually set up correctly out of the box when purchasing new equipment such as routers and modems for their internet service provider (ISP). However, understanding these basics will help you better configure the device to meet your needs.
