DHCP protocol: Do you know how to use it?
In the digital world, some resources make our daily lives much easier without us even realizing it. Among them, the DHCP protocol stands out, which is related to the Dynamic Network Address Configuration Protocol and allows machines to automatically have an IP address.
This protocol began to gain prominence in 1993 and is fundamental for network administration. Therefore, we prepared this post to discuss in more detail its function, the modes of functionality, and the benefits of using it. Get your questions answered now and enjoy reading!
What is the function of the DHCP protocol?
The DHCP protocol becomes important in better managing a network. For example, let’s assume you have to manage a network of 100 or more computers. It would be practically impossible to assign an IP number with all the necessary parameters for each one.
So, for this mission, the DHCP protocol comes in — through it, a server will be able to automatically distribute different IP addresses to all computers as they make the network connection request. This way, this distribution of IPs is carried out in a pre-defined range on the server.
In other words, this protocol uses a client-server model so that, when the user connects to a network, it sends packets with a DHCP configuration request and its server manages a fixed range of available IPs with parameters and important information (domain name, default gateway, DNS, etc.).
Finally, when this server receives a request, these addresses are delivered and configured to the client.
How does it work in practice?
Before we delve into how it works, it is necessary to understand how the DHCP protocol can be managed. In general, it takes place in three forms: automatic, dynamic, and manual. Understand in detail about each one:
- automatic — this is when several IP addresses, which are within a range, are defined to be used within the network. Thus, whenever one of the computers requests a connection, one of these IPs will be allocated to the related machine;
- dynamic — it is similar to what happens automatically, however, the computer’s connection to the related IP is limited for a certain pre-configured period that varies according to the network administrator’s needs;
- manual — the DHCP protocol transports the IP address according to the MAC (Medium Access Control) value of each network card and each computer will only use this IP address. Therefore, this feature is used when the machine must have a fixed IP address.
The fact is that the DHCP protocol has different platforms that provide an efficient solution to assist network administrators. It works at the application layer that dynamically assigns the client’s IP address. It even happens through the exchange of a series called DHCP transactions with four initial steps. Let’s get to know each of them.
DHCP Discovery
The DHCP client connects to a network, or wireless cable, on which it transmits messages to discover DHCP servers. Thus, the frame with this DISCOVER message arrives at the server.
DHCP Offer
After the server receives the DHCP DISCOVER message, it will suggest or provide an IP address to the client who will send an offer message. It will include the IP address proposed for the client, the client’s MAC address, subnet mask, server IP address, default gateway, DNS address, and its concession information with the following steps:
- address that will be proposed to the customer (192.168.1.10);
- subnet mask for identifying the subnet space (255.255.255.0);
- Default gateway IP for the subnet (192.168.1.1);
- Server IP with name translation (8.8.8.8).
DHCP Request
After the customer receives the offer, they will be asked for official information by sending the REQUEST message via unicast. It is important to note that it may receive several DHCP offers because there are several servers, but only one offer at a time.
DHCP confirmation
The server sends an acknowledgment to the client confirming the DHCP protocol lease. Thus, the IP configuration is finalized and completed so that new configurations can be used when necessary.
What are the benefits of using DHCP?
The DHCP protocol is capable of providing accurate IP configuration allows it to be used once and automates address administration. Without it, the professional would need to add or revoke everything manually, which would be disadvantageous as it would take more time.
Furthermore, it will be possible to control and automate which device you will determine the IP address, in addition to centralizing information to optimize all work and facilitating the process of changing scopes, addresses, and endpoint security. Therefore, you can integrate and distribute them to a new terminal to be used.
However, in the DHCP protocol, there are some disadvantages. One of them is not having security methods when it comes to customer identification. This way, when he joins the network, there will be no restrictions. One way to solve this problem is to use relay agent data by having DHCP mark it as it arrives on the network.
This authentication is known as network access control (NAC) or 802.1x and this process is quite simple to implement. Furthermore, the DHCP protocol makes managing the entire network easier for administrators, after all, carrying out this entire protocol manually can be laborious.
Optimization in configuration management is another advantage of the DHCP protocol. Thus, it helps with the update frequency so that it is done efficiently and automatically in server communication.
In short, having the DHCP protocol allows for better network monitoring and may even make it impossible for network errors to occur, such as the duplication of addresses that generate IP conflicts or even incorrect typing of a subnet mask.
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