The problem, when the DNS server does not respond, persistently pursues users of the Russian segment of the global network. Although, you can easily get rid of most of the difficulties that arise simply by reconfiguring DNS for the proper functioning of the Internet on the user's computer.
If the DNS server is unavailable, and all the user's devices are in good condition and there are no financial debts to the provider, then, as a rule, there is no access to the World Wide Web due to incorrect settings. You just need to know how to fix errors in the settings and there will be no difficulties with Internet access.
Below is a detailed guide to troubleshooting the problem, you just need to strictly follow all the sequential steps of the instruction. 
What are DNS servers for?
What is it and why are DNS servers required? When going to any site on the Internet, a certain directory on the server becomes available to the user. This section contains information that the Internet browser of the user's computer reproduces in the form of a familiar web page. All servers have an individual "IP" through which you can log in.
The main requirement for DNS is that they provide accurate redirection from the "IP address" to domains that no longer have a numeric address, but an alphabetic one ... ". On the world wide web, this site has an IP - 46.36.219.125..36.219.125, because machines can only understand numeric codes, not alphabetic ones. However, sometimes it happens that the servers do not work properly and then an unpleasant message is displayed on the user's monitor: "The DNS server is not responding."
A yellow triangle with "!" inside.
Next, we will consider step by step what to do in such a situation.
Troubleshooting instructions
You must perform the following sequential steps:
When the above service is running, but there is still no Internet access, then the following steps are required:
In the absence of access to the Internet after careful execution of the above steps, most likely there are errors directly in the work of Windows. You can use the well-known feature to roll back the OS to a time when everything was working fine. To this end, only a few steps need to be taken:
- Open the "System Restore" window through "Start";
- Select a restore point and roll back the system.
- Restart your PC.
The most common difficulties
Often, such difficulties appear when users incorrectly entered the network settings or due to infection of the computer with malicious applications. Therefore, it is recommended to make sure that the anti-virus databases of the installed utility are up-to-date and that the firewall is active.
Sometimes problems appear due to incorrectly entered parameters in the interface of your router or banal omissions of some items in its settings.
The modern Internet is nothing more than a multitude of different computers, laptops and mobile devices connected to each other in one network. In fact, all these devices are servers. After all, each of them has an IP address that is unique. It is thanks to IP that the identification of devices in the global network occurs.
At the same time, the Internet requires two types of servers: primary and secondary. The first serves to host user sites. Depending on how much information is sent and received, a different number of sites can be stored on the server - from one (facebook.com, mail.ru, odnoklassniki.ru) to many thousands. The second type is represented by helper servers, which help the main network to operate by providing general communication. DNS servers are a type of such assistive device.
What is a DNS server and what is it used for
A DNS server is essentially a computer, but not really. It serves to host a distributed database, which is part of the Domain Name System (DNS), which is used to receive and transmit and transmit information about domains of interest to users. DNS servers are connected to the network and interact with each other according to a certain protocol.
A simpler description could be given. Using the DNS server, it is determined that the site name we are used to is its IP address. This information is stored in a constantly updated database.
Let's consider the whole sequence in practice. The browser in which the user opens the site initially contacts the DNS server and notifies him that he wants to find and get to the site whose address is entered in the text field of the address bar. Move on. The DNS server determines by its base where on the network a site with this name is located, comparing it to the IP address of the server with the resource located on it, and sends a request there. As a result, a response is generated, consisting of a set of various files that make up the site itself (HTML documents, images and tables, CSS styles) and sent to the user's browser.
Where are the DNS server settings and how to find out its address in Windows 7
Consider a situation when a user on his computer running Windows 7 is quietly "surfing" the Internet. This means that the DNS server is up. You can verify this by going through the "Administration" tab of the control panel in the "Services" menu and view the status of the DNS client. The service must be enabled when the automatic startup type is selected.
In order to find out the address of the DNS server, use the ipconfig / all command by entering it in the command line of the cmd.exe utility launched as administrator.
How to install and configure: instructions
DNS server connects when configuring network protocol.
Startup sequence:
It should be noted that this automatic configuration is only possible if the DHCP Client service is enabled, which enables the DHCP server to start and operate on the network. Its settings can be viewed and changed by selecting the appropriate item in the open system services window of the "Administration" tab of the control panel.
Automatic configuration uses the provider's DNS servers. This is not always advisable, as difficulties can arise. For example, the provider's servers are not always able to cope with the arising load and do not perform filtering. In this case, it is preferable to connect through large well-known companies.
Yandex DNS servers:
Google DNS servers:
OpenDNS DNS servers:
Depending on the selected company, a pair of addresses is entered in the properties window of the Internet protocol into the fields of the preferred and alternative DNS servers when the radio button for their use is checked.
Possible problems and ways to solve them
If you are having problems accessing the Internet, then do not rush to get upset. It is quite possible that this happened due to a malfunction of the DNS server.
Main problems:
It may happen that your provider has enabled blocking of some DNS servers, or the addresses specified in the network protocol settings have become unavailable. The solution to the problem is very simple. First, try changing the addresses of the DNS servers, and if this does not work out, then turn on their automatic receipt. If the problem is not resolved, then you should look for another reason or contact the service center.
Video: What to do if DNS is not responding and how to fix other issues
DHCP server and how it differs from DNS
A DHCP server refers to an auxiliary type of servers containing a network protocol that provides dynamic configuration of a node at the stage of automatic configuration of any network device connected to the Internet. In this case, the network administrator specifies only the address range. In this case, there is no manual setting and, accordingly, the number of errors that occur is reduced. This is because the server automatically distributes addresses between computers in accordance with the specified range. Most TCP / IP networks use DHCP.
WhatDNS
DNS (domain name system) is a system that ensures the work of the domain names of sites we are used to. Communication between devices on the Internet is carried out by IP addresses, for example: "192.64.147.209". However, remembering IP addresses is difficult, so human-friendly domain names have been invented, for example: "google.com".
The computer / server does not store a table of domains and their IP addresses. More precisely, it does not store the entire table, but temporarily stores data for frequently used domains. When a website domain is entered in a browser, the computer automatically recognizes its IP address and sends a request to it. This process is called "domain resolving".
Let's see what the DNS system consists of and how it works.
How does it workDNS
The domain name system consists of the following components:
Hierarchical structure of domain names:
- Top-level domain zones (first level) - for example: "ru", "com", or "org". They include all domain names included in this zone. Any domain zone can include an unlimited number of domains.
- Domain names (second level domain zones)- for example: "google.com" or "yandex.ru". Because Since the system of domain names is hierarchical, "yandex.ru" can also be called a subdomain of the higher-level "ru" zone. Therefore, it is more correct to specify the domain level. However, in practice, a domain zone of any level is simply called a "domain".
- Subdomains (third level domain zones) - for example: "api.google.com" or "mail.yandex.ru". There can be domain zones of 4, 5 levels, and so on.
Note that "www.google.com" and "google.com" are actually different domains. We must remember to include A-records for each of them.
DNS server or NS (name server) server- supports (maintains) domain zones that are delegated to him. It directly stores the resource record data for the zone. For example, that the server hosting the site "example.ru" has the IP address "1.1.1.1". The DNS server responds to all queries regarding these domain zones. If he receives a request for a domain that is not delegated to him, then he asks for an answer from other DNS servers.
DNS records (resource records) Is a set of records about the domain zone on the NS server, which store the data necessary for DNS operation. Based on the data in these records, the DNS server responds to queries by domain. The list of records, and their meaning, you can find below.
Root DNS Servers (at the moment there are 13 in the world) store data about which DNS servers serve the top-level zones.
DNS servers for top-level domain zones- store information which NS servers serve this or that domain.
In order to find out the IP address of a domain computer / server contacts the DNS server, which is specified in its network settings. Usually, this is the DNS server of the ISP. The DNS server checks whether the domain is delegated to it or not. If so, it immediately responds to the request. If not, it requests information about the DNS server serving this domain from the root server, and then from the top-level domain zone server. After that, it directly makes a request to the NS server serving this domain, and broadcasts the response to your computer / server.
Data caching used on all devices (computers, servers, DNS servers). That is, they remember the responses to the last requests that came to them. And when a similar request comes in, they just respond the same as the previous time. For example, if you open google.com in your browser for the first time after turning it on, the computer will make a DNS request, and on subsequent requests it will take the data that was sent to it by the DNS server for the first time. Thus, for popular requests, it is not necessary to go through the entire chain every time and generate requests to NS servers. This significantly reduces the load on them, and increases the speed of work. However, as a result, data updates in the DNS system do not happen immediately. When the IP address of the domain changes, information about this will be distributed over the Internet from 1 to 24 hours.
Domain registration / allocation
Each first-level domain zone has its own organization, which sets the rules for domain allocation and ensures the operation of this zone. For example, for the RU, SU and RF domain zones, this is the Coordination Center for the national domain of the Internet https://cctld.ru. These organizations set the rules of operation and technical requirements for domain registrars.
Domain registrarsAre companies that directly register new domains within the first-level domain zone for end customers. They organize technical interaction with the domain names registry. In their personal account, the domain owner configures which DNS server will support the domain.
Domain administrator (owner)- the person who directly owns the rights to the domain name. He can manage the domain, from him the registrar accepts requests for changes.
Domain delegation- specifying DNS servers for it that will serve it.
The mainDNS records
The following primary DNS (resource) records exist:
A - contains information about the IPv4 host (server) address for the domain. For example, 1.1.1.1.
ААА - contains information about the IPv6 host (server) address for the domain. For example, 2001: 0db8: 11a3: 09d7: 1f34: 8a2e: 07a0: 765d.
MX - contains data about the domain mail server. In this case, the name of the mail server is indicated, for example, mail.example.com. Because a domain can have several mail servers, then for each of them the priority is indicated. The priority is set by a number from 0 to 65535. In this case, "0" is the highest priority. It is accepted by default to indicate priority "10" for the first mail server.
TXT - additional information about the domain in the form of free text. The maximum length is 255 characters.
SRV - contains information about hostname and port number, for specific services / protocols in accordance with RFC 2782 http://www.rfc-editor.org/rfc/rfc2782.txt. Contains the following fields:
- _Service._Proto.Name (Example: _jabber._tcp.jabber), where:
- Service: the name of the service (example: ldap, kerberos, gc and others).
- Proto: the protocol through which clients can connect to this service (example: tcp, udp).
- Name: the name of the domain that hosts this service.
- Priority - as for MX records, it indicates the priority for this server. It is set by a number from 0 to 65535. In this case, "0" is the highest priority.
- Weight - The relative weight to distribute the load between servers with the same priority. Set as an integer.
- Port - the port number on which the service is located on this server.
- Purpose - the domain name of the server providing this service.
NS is the name of the DNS server that supports this domain.
CNAME (canonical name) - used to redirect to another domain name. For example, the server name has changed from example.com to new.com. In this case, in the "Alies" field for the cname entry, you must specify - example.com, and in the "Canonical name" field - new.com. This way, all requests to example.com will automatically be redirected to new.com.
SOA is the basic domain record. It stores the domain name itself and the TTL of the domain data. TTL (time-to-live) determines what period of time the DNS server, having received information about the zone, will store it in its memory (cache). The recommended value of 86400 is 1 day. The value is specified in seconds.
Hello dear readers of the blog site. This article, among a number of others, is intended to, in general terms, without abstruse phrases and definitions, give an ordinary user information that would help him understand the essence of one of the main components of the network, namely the domain name system (DNS), inextricably linked with concepts such as hosting, domain and site IP ().
For a deeper understanding of the essence of today's topic, it may be useful for you to familiarize yourself with the topic, since it is the web resources that are located on the Internet that are the main objects of application of the DNS system.
Below we will carefully analyze the nuances of the operation of DNS servers, with the help of which the operation of the entire system is practically implemented. They will be useful for both regular users and novice webmasters (administrators) of sites.
What is the CSN system for and what is it?
So, first, let's define the terms. DNS abbreviation stands for Domain Name System, which in Russian means “domain name system”.
DNS is a special distributed system on the Internet for linking the domain names of the corresponding web resources and the IP addresses of network nodes, or hosts (computers or servers) on which these web resources are located.
Each node is assigned to connect to it, represented by a set of numbers (in the case of the IPv4 version) or a symbolic combination (IPv6), with the help of which this or that web resource on the Internet is identified. As in real life, each person can be found by his address (city, street, house and apartment number), so the ip allows you to determine where any web resource on the network "lives". For example, here's what the Odnoklassniki website looks like:
217.20.155.13
Agree, the numerical set is not very informative and is difficult for people to remember, but the World Wide Web was created for living users. Another thing is the domain name () ok.ru (in the old edition "odnoklassniki.ru"), which says much more about this popular social network of the Russian Internet. Therefore, DNS was introduced, where, to facilitate the perception of each web resource by the IP address, a correspondence was introduced in the form of a domain name.
For those who are just starting their way in webmastering and are trying to create their first website, I think it will be interesting to learn about how, which is related to. After all, it is on the servers (which, roughly speaking, are super-powerful computers) of hosting providers and all web projects are located.
But back to our rams. We figured out that DNS implements such an addressing system that makes it possible match the IP of the site with its domain name.
At the stage of the inception of the Internet, there was no such mechanism in its present form, so all the work on identifying sites for accessing them was assigned to the hosts file, which was present (and is still present) on the computer of each user.
217.20.155.13 ok.ru
This was tolerable as long as the network was small and there were only a few network nodes. But as soon as the Internet began to gain momentum and expand, the almost manually updated hosts file lost its relevance in this part of its functionality. But even though its function of identifying websites has shifted to the DNS system, it is also involved in some way.
This is as follows. When you enter the URL () of a site containing the name of its domain into the address bar of the browser (), the browser first of all accesses the hosts file. In the modern version, there is only one line by default, namely: 127.0.0.1 localhost.
But you can edit this file yourself and, depending on the nature of the changes, speed up access to certain resources or block some sites.
The hosts file often becomes the object of all kinds of viruses, as a result of which the user can be redirected to some dubious project (). That is why every self-respecting antivirus program protects the hosts file in all available ways. The hosts file digression is behind us. Move on.
How do DNS servers work?
Well, now we will summarize the above in some way, adding some details regarding servers designed to identify all sites by their domain names in order to display the desired pages in the browser.
So, first of all, the browser will check the hosts content as the most easily accessible source relative to the domain entered in the address bar as part of the url and, only after it does not find the required entry there, will turn to the nearest DNS server included in the system. It is the set of DNS servers that make it possible to implement the whole thing in practice.
The DNS server contains special software for maintaining the domain name system. He can be responsible for one or another zone of domains and redirect requests to higher hierarchy servers.
In response to the request, the server sends the necessary information to the browser, and since the DNS has a hierarchical structure, if it is absent, the next Domain Name server is requested. In a simplified form, this scheme of work can be represented as follows:
Only after receiving the IP-address will the browser send a request to the hosting server to obtain the files needed to display the desired page. Given the current speed of the Internet, even such a seemingly multi-level operation takes a minimum of time.
But even here there are hidden reserves for increasing the speed of opening a website's web page. The fact is that the browser stores in the cache () all data received from DNS servers for those web projects that were visited by the owner of this computer.
Therefore, when the user reopens such web resources, the browser will no longer need to repeat the entire chain of requests, so the pages will open much faster. Of course, the cache is stored only for a certain time, but nevertheless, the very existence of such an opportunity makes life easier for users.
Now it is necessary to highlight one significant nuance that concerns concepts "Server IP" and "Site IP"... Based on the scheme indicated in the screenshot above, it is quite logical to assume that each domain name must correspond to a unique IP. For large resources, each of which is located on, this statement is quite true.
But this is not always the case. I will say more, there are hundreds of thousands of sites on the Internet, the lion's share of which "live" on (shared servers). This means that all sites that are located on the same server will have the same IP.
One IP address can correspond to several sites with different domains.
The DNS system does not fail in any way when using a split server. After all, a request from a browser via the HTTP () protocol comes with an indication of the domain name of the site and its page that needs to be displayed.
And therefore, the location of the necessary files belonging to a specific project will be immediately determined using the server software, and they will be promptly transferred to the user's browser:
If you remember, I compared the IP above with the address of the person's residence. So, if a dedicated server on which the only web resource is located can be compared with a private dwelling, when only its number (IP) is relevant in the address, then a shared server is quite comparable with any multi-apartment building, where the house number is IP acts, and the role of the number of a particular apartment is played by the domain name of the site.
We considered the situation when different sites with the same IP may be present in the DNS system, since they are located on the same server of a specific hosting provider. But the reverse is also true.
A site with a specific domain can have several IP addresses at once.
Practically different IPs for one web resource are needed, say, to enhance security (for example, to ensure the possibility of switching during DDOS attacks), as well as in other cases, which we will not analyze in detail for now.
Hosting NS servers for the site and their role in DNS
The information presented above is quite sufficient for an ordinary user seeking to replenish the knowledge box. But for webmasters and those who wish to significantly improve their educational level, you may need something that we will talk about further.
We will talk about the importance of the part of the DNS servers participating in the system that hosting providers have at their disposal. Them most often called NS servers... The workflow of the domain name system shown in the previous figure is greatly simplified and does not include NS servers. But the following chain reflects the essence in more detail:
Although this diagram does not contain all the nuances, it is nevertheless more informative and quite sufficient for a general understanding of today's topic. Despite the fact that the screenshot above contains the necessary explanations, I consider it my duty to describe in more detail the procedure for identifying the site and its subsequent display in the browser:
1. First, the browser sends a request to the DNS server of the Internet provider, with which the user has a contract for the provision of network connection services. If the user has previously visited this web project, then the cache already contains the IP address of the server on which it is located.
In this case, further actions along the full chain will not be required, and the required IP will be immediately transferred to the browser, after which an appeal to the corresponding hosting server will follow, as a result the required page of the site will be opened.
2. If no record of domain and IP correspondence is found, then the Internet provider will send a request to one of root DNS servers the desired zone, of which there are a few in the network, where the data is updated several times a day.
3. The root server cannot immediately give a "domain name - IP" match, but it will transfer the addresses of just those NS servers that belong to the hoster where the desired site is located (for example, for Sprinthost, whose client I am, these addresses are : ns1.sprinthost.ru and ns2.sprinthost.ru). To make this possible, the site owner. Therefore, if you are a novice webmaster, be sure to read about it by clicking on the link just provided.
5. As a result, the required IP will be transferred along the chain "NS-hosting server" - "DNS server of the Internet provider" - "user's computer".
6. Well, and the last link in this chain is a browser request to the hosting server using the received IP address, after which the files on it will be transferred to the page that the user requested by entering the corresponding URL in the address bar.
DNS is a service that provides exchange between different network segments. Its use can significantly reduce the time spent searching for information. In this article, you will learn about the basic principles of the service, as well as the methods and forms of data transmission on the Internet.
How does it work
At the dawn of the Internet, there was a "flat" naming system: each user had a separate file that contained lists of contacts he needed. When he connected to the World Wide Web, his data was sent to other devices.
However, due to the rapid development of the Internet, it was necessary to simplify the exchange of data as much as possible. Therefore, it was divided into smaller segments, domains. In turn, they are divided into subdomains. At the top of the address submitted in the nominal form is the root - the main domain.
Since the Internet is an American development, there are two types of primary domains:
- generic domains that belong to US institutions:
- com - business organizations;
- gov - government offices;
- edu - educational institutions;
- mil - military missions;
- org - private organizations;
- net - internet service provider.
- other country's root domains have two letters.
The second level consists of abbreviations of cities or regions, and the third order domains denote various organizations and enterprises.
The dot acts as a separator between domains of different orders. There is no full stop at the end of the name. Each individual dotted domain is called a label.
Its length must not exceed 63 characters, and the total length of the address is 255 characters. Basically, Latin, numbers and the hyphen sign are used, but several years ago they began to use prefixes based on other writing systems. The letter case does not matter.
Servers are computers that contain a list of other objects within the same level of the network, which makes it possible to speed up the exchange between users. They became the basis of the new system.
Each layer of the network must have its own server, which contains information about the addresses of users of its segment.
The search for the required data goes like this:
DNS basics
A multi-domain host is called a zone... Its file contains the main parameters of its segment. This includes FQDN or Fully Qualified Domain Name information. If such an entry ends with a period, it means that the object name is specified correctly.
There are several types of computers that serve DNS:
- master - the main agent of the network. He can change its configuration;
- slave - devices of the second order. They serve clients on par with master and can replace it in case of failure. This relieves the network;
- caching. Contains in its information about domains of extraneous zones;
- invisible. Not in the zone description. Most often, this status is assigned to users with the master status in order to protect them from attack.
- recursive. If the server does not contain the necessary information, in this case it learns the necessary data from higher-level computers and sends a response to the client. This reduces the number of requests and saves time and your traffic;
- iterative. The server sends a ready-made response, selecting information only from its own cache (memory). If he does not have suitable data, then he provides a link to other computers. The browser then navigates to that address.
The user can send one of two types of requests to them.
The browser sends it through the resolver program:
There are two types of responses:
- authoritative - if data is sent from devices that serve the network;
- non-authoritative. It is sent by an outside computer that receives the necessary data from its own cache or after an iterative request.
Video: DNS Service
Names and IP addresses
DNS provides translation of site names into IP addresses. On the Internet, every device can be tracked by 2 main parameters - domain name and IP address. They can be assigned to a user's computer, network printer, or router.
However, this is very arbitrary, since a computer may not have a domain name, but use several addresses. In addition, each IP address must match all domain names. However, a domain can only contain information about one IP address.
Working hours
Servers can operate in modes:
- maintenance of your own zone. Data exchange takes place between master and slave computers. However, requests from unauthorized users are not accepted;
- executing a recursive question;
- forwarding - the server sends a request to another zone.
Changing DNS parameters
Typically, these parameters are set automatically by the network. In order to reset the data, go to the "Network Connections" section.
After that, you need to go into the protocol used to maintain the network.
In the "Properties" section, you can set the required parameters. Usually, the main IP address of the server and the alternate one are indicated.
Message format
The messages that are used to exchange information by the service begin with a 12-byte header. This is followed by an identification field that allows you to determine which request the response came to.
The flags field (next 16 bits) includes information:
- message type;
- operation code;
- identification of authority (i.e. shows whether the serving computer belongs to the network);
- TC flag. Displays whether the message arrived truncated or complete.
- recursion flag i.e. requests the server to send requests to higher-order computers;
- recursion capability flag. Indicates the server's ability to forward messages;
- return code. Displays whether a response was sent with errors or not.
The last 16-bit field shows the total number of parameters taken into account.
DNS query questions
Part of a resource record in a response
Any response contains information about the party that sent the message. It contains the following data: response, server authority and additional information about it.
In addition to them, the message contains:
- domain name;
- type of request;
- the expiration date of the cached version;
- resource record length - an estimate of the amount of information.
Pointer queries
Pointer queries are directed to find the page in inverse mode, i.e. search for a resource name by IP address, given as a dotted text string.
To send it, the host address is written in the opposite order with the addition of a specific suffix (most often in the form in-addr.arpa).
The operation can be performed if the resource contains a PTR record. This allows you to transfer control of the zone to the owner of the IP addresses.
Resource records
This is a list of the main programs used by the service. These records are unique within the same domain. There may be duplicates of these records at different levels of the network.
This data includes the following types of records:
- SOA –Start of powers. It allows you to match the domain and the computers serving it. They also contain information about the expiration date of the cached version, and the contact person who serves the server of a certain level;
- And contain a list of IP addresses and their corresponding hosts. They allow you to identify the address of domain resources;
- NS (Name Server) include a list of computers that serve the domain;
- SRV (Service) displays all the resources that perform the most important functions of the service;
- MX (Mail Exchanger) allow you to automatically configure the distribution of data to serving computers within the same domain;
- PTR (Pointer) are used to find the name of a resource if the user knows its IP address;
- CNAME (Canonical Name) allow a server to be referred to by multiple aliases in a service.
Caching
To find the information you need, the browser can search for information in three segments. First, the required data is searched using a DNS service, i.e. at the local level. They can be found if the computer contains a Hosts file.
However, if the operation fails, the client issues a request.To speed up the search for information, cached servers are used. If it doesn't find the data it needs, then it executes a recursive query. When served, it copies data from other networks.
This allows you to save traffic by not later turning to authoritative users. But an open record remains valid for a limited time. Its expiration date is set in the zone file. By default, the minimum is 1 hour.
UDP or TCP
The service supports both UDP and TCP.
UDP is used to send messages over wide area networks. The size of messages sent via this protocol is limited. Incomplete responses contain the TS tag. This means that the response size exceeded 512 bytes, so the rest did not reach the computer.
It is less reliable because it does not have a specific request response timeout. However, such a system is suitable for transmitting a huge amount of information.
TCP is used to transmit such data because it allows any amount of data to be received, divided into segments of a certain size.
It is also used by secondary servers when they request data from the host computers every three hours to find out if the network configuration file has been updated.
The DNS service has a complex hierarchical structure. However, the server system provides flexible and fast interaction between all users and devices of the Network.
To find out the necessary information, the client sends a request. The response contains basic information about the object of interest and the computer serving the zone. To carry out this exchange, the UDP and TCP protocols are used.
