DHCP or also known as dynamic host configuration protocol is specialized in simplify and improve the accuracy of the . In this way it has the ability to network devices quickly and easily, which has made it an essential method to ensure that devices can join in networks and are correctly configured.
Therefore, this protocol aims to be able to greatly reduce the errors that occur when IP addresses are assigned manually. They also have the ability to keep IP addresses individually. In this way, this protocol is one of those in charge of allowing all works correctly, quickly and easily.
Taking into account that this tool is not well known by everyone, nor is it a term widely used by people Here we are going to explain a little more about what these protocols are, what they are for and how they work in computing. To do this, follow in detail everything that we will teach you in this post.
What is a DHCP server and what is it for in computer networks?
These servers are those that allow a computer that is connected to a network be able to get your config dynamically. Also, it’s a network protocol which is used in IP networks where a DHCP server is in charge of automatically assigning an IP address and other information to every host on the network. All this allows you to communicate efficiently with others end points.
Thus, the main objective of this tool is to be able to simplify network administration. It works the same way to be able to distribute the IP addresses of a network, as well as assign the subnet mask, the domain name server address, the default gateway address and many others Settings relevant.
This is how this server has a dynamic IP address list and the goes assigning clients as they become freetaking into account at all times what clients have been in possession of those IPs, how long they have used it, and to whom it has been assigned afterwards. This allows customers of a IP network are able to get their configuration parameters automatically.
How does the DHCP protocol interact with the other Internet protocols?
DHCP server is the one who takes care of distribute IP addressesso it will be the base for all dhcp requests so you need to have one fixed IP address. Therefore, in a network you can have a single computer with a fixed IP address. The basic communication system is BOOTP with the UDP frame. When the machine starts it does not have any information about its Network Configuration, so there is nothing special that the user has to do to be able to get ip address.
In this type of case, it is necessary to transmission technique: This allows you to can find and communicate with a DHCP server. To do this, the team simply has to sends a special broadcast packetan example of this would be “Transmission at 255.255.255.255 with additional information such as the type of request, the connection ports and many other elements. All this through a local network.”
once the DHCP receive the transmission packetanother transmission packet containing all the information that is requested by the client. In this way it can be said that a single package is more than enough for the protocol works correctly. But it should be mentioned that there are different dhcp packet types, which can be issued either from the server or servers to the client or from the client to the servers.
These types of packages are the following:
- DHCPDISCOVER: Used to locate servers DHCP available.
- DHCPOFFER: It is the server’s response to a packet DHCPDISCOVER, which contains the initial parameters.
- DHCPREQUEST: For various customer requests.
- DHCPACK: It is the response from the server that contains the parameters and the client IP address.
- DHCPNAK: It is the response from the server to indicate to the client that its lease has been closed, or when it has been announces to the client that one of the network settings is wrong.
- DHCPDECLINE: The client is responsible for announcing to the server that the address already in use.
- DHCPRELEASE: In this case the client releases his IP address.
- DHCPINFORM: The client decides to request the local parameters, already have an IP address.
How does communication between client and server work in DHCP?
In order to understand this much better, it is necessary to be able to know how the communication between the client and the server occurs or works. Taking into account that this is where it occurs automatic address assignment Through the dynamic host configuration protocol.
This entire process consists of four steps that we will show you below:
- in the first step the DHCP client sends a DHCPDISCOVER packet to address 255.255.255.255 from address 0.0.0.0. with this so-called wide diffusion or broadcastit is here where the client establishes a contact with all the other members of the networkwith the purpose of locate dhcp servers that are available. Yes there is only one serverthen the configuration will be very simple.
- All servers listening for requests in port 67 respond to the request client with a DHCPOFFER packetwhich contains a free IP address. The of the client and the subnet mask, as well as the server ID and IP address.
- The next thing will be the dhcp client select a package and contact the corresponding server in this case DHCPREQUEST. All the other servers will also receive this message so that they remain informed of the election. Pursuant to this notice, the customer will also asks the server for confirmation of the data that has been offered. So this answer also works for confirm previously assigned parameters.
- Finally, the server takes care of confirm TCP/IP parameters and he sends them from new to customerthis time through DHCPACK packet. This package contains other data such as SMTP, POP3 or DNS servers. The dhcp client It decides to save all the data it has received locally and connects to the network. In the event that the server does not have any most available addressthe processthat of the IP would be assigned to another client, to which it would respond with DHCPNAK.
Once all this is done, the assigned address is stored in the server’s database along with the MAC address of the client. In this way the configuration is made permanent. allowing so the device connect to the network always with that address that has been automatically assigned to you and that is no longer available to any other customer.
This means that new customers they will not be able to receive any addresses if all of them have already been assigned, even though some IPs are no longer being used. All this has caused a significant expansion in dynamic directionsand in some cases to manual assignment via DHCP server.
Advantages and disadvantages How convenient is it to use these servers?
Considering everything mentioned above in the post, it is very important to know What are the benefits of this protocol and what are its respective disadvantages?.
That is why we are going to show you the benefits and drawbacks that can be achieved when using these types of servers:
Advantage
- count on this dhcp protocol can offer certain advantages, one of them is that it allows you to save time on setupwhile the connection and disconnection of equipment is done automatically. This will allow you save time configuring IP addresses manually.
- Other advantages that you can get is the simplification of the Network Configurationin this case the user simply must connect the network cable or connect to the WiFi network, so you will not need any kind of knowledge for that IP address assignment works on its own.
Disadvantages
- Having this protocol activated can also cause you some inconveniences, especially in safety where they are most affected Wi-Fi networks. if found DHCP server enabledan intruder can have an IP address as soon as you connect. While if you do not have said protocol manual assignment will be requiredand in the case that it has been modified from manually the range of IPs, the hacker or cybercriminal is going to have problems.
- Another inconvenience that can be achieved when having DHCP enabled it’s going to make it difficult to identify devices on network and configuring services that require static IP addresses how would it be open or close ports.
DHCP Server Security How reliable and secure are these servers?
One of the things that most worries about using this protocol is the security of the serversespecially since it is considered that network security Wifi is often affected by them. Thus the dhcp usually has a weak point and that is that it can reach be easily manipulated. The client usually makes a discretionary appeal to all dhcp servers who can respond to your request, so any attacker with the necessary knowledge can break into the network.
In a very simple way and pretend to be one of them if you had access to it. All this is called Rogue or corrupt DHCP server. the hacker clearly going to try preempt your response to the legitimate server, trying so to get success to be able to send the manipulated parameters. If not sent the gateway then one is assigned subnet for each client or responds to all requests with the same IP address.
All this will allow the attacker to initiate a denial of service attack. This will allow it to be entered into the router using fake data about the gateway and DNS, thus allowing him to be in the position to copy and divert all data traffic. All this is done with the aim of seizing sensitive information What passwords, postal addresses or bank and personal details.
Therefore, when using this protocol it is necessary to implement all necessary security measures that allow you to enjoy all the advantages offered by these servers, without having to worry about suffering some of these consequences. For this it is necessary to have a absolute protection about any kind of both external and internal attackas well as the constant monitoring of all processes carried out on the network.
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