Domain Name System (DNS) Domain name system. DNS server - what is it? DNS Unlocker - what is it? Domain name system dns in brief

The correspondence between domain names and IP addresses can be established either by local host tools or by means of a centralized service. In the early days of the Internet, a text file with the known name hosts was manually created on each host. This file consisted of a number of lines, each of which contained one “IP address - domain name” pair, for example 102.54.94.97 - rhino.acme.com.

As the Internet grew, hosts files also grew, and creating a scalable name resolution solution became a necessity.

This solution was a special service - Domain Name System (DNS). DNS is a centralized service based on a distributed domain name-IP address mapping database. The DNS service uses a client-server protocol in its operation. It defines DNS servers and DNS clients. DNS servers maintain a distributed mapping database, and DNS clients contact servers with requests to resolve a domain name to an IP address.

The DNS service uses text files in much the same format as the hosts file, and these files are also manually prepared by the administrator. However, DNS relies on a hierarchy of domains, and each DNS server stores only part of the network's names, rather than all of the names, as is the case with hosts files. As the number of nodes in the network grows, the problem of scaling is solved by creating new domains and subdomains of names and adding new servers to the DNS service.

Each name domain has its own DNS server. This server can store domain name-IP address mappings for the entire domain, including all its subdomains. However, this solution turns out to be poorly scalable, since when adding new subdomains, the load on this server may exceed its capabilities. More often, the domain server only stores names that end at the next lower level in the hierarchy than the domain name. (Similar to a file system directory, which contains records about files and subdirectories that are directly “included” in it.) It is with this organization of the DNS service that the name resolution load is distributed more or less evenly among all DNS servers on the network. For example, in the first case, the DNS server of the mmtru domain will store mappings for all names ending in mmt.ru: wwwl.zil.mmt.ru, ftp.zil.mmt.ru, mail.mmt.ru, etc. In In the second case, this server stores mappings only of names like mail.mmt.ru, www.mmt.ru, and all other mappings should be stored on the DNS server of the zil subdomain.

Each DNS server, in addition to the name mapping table, contains links to the DNS servers of its subdomains. These links link individual DNS servers into a single DNS service. Links are the IP addresses of the corresponding servers. To service the root domain, several DNS servers that duplicate each other are allocated, the IP addresses of which are widely known (they can be found, for example, in InterNIC).

The procedure for resolving a DNS name is in many ways similar to the procedure for the file system searching for a file address by its symbolic name. Indeed, in both cases, the compound name reflects the hierarchical structure of the organization of the corresponding directories - file directories or DNS tables. Here the domain and domain DNS server are analogous to a file system directory. Domain names, like symbolic file names, are characterized by naming independence from physical location.

The procedure for searching for a file address by symbolic name consists of sequentially viewing directories, starting with the root. In this case, the cache and the current directory are first checked. To determine an IP address from a domain name, you also need to view all DNS servers that serve the chain of subdomains included in the host name, starting with the root domain. The significant difference is that the file system is located on one computer, and the DNS service is distributed by its nature.

There are two main DNS name resolution schemes. In the first option, the work of finding an IP address is coordinated by the DNS client:

The DNS client contacts the root DNS server with the fully qualified domain name;

The DNS server responds with the address of the next DNS server serving the top-level domain specified in the high part of the requested name;

The DNS client makes a request to the next DNS server, which sends it to the DNS server of the desired subdomain, and so on, until a DNS server is found that stores the mapping of the requested name to the IP address. This server gives the final response to the client.

This interaction pattern is called non-recursive or iterative, when the client itself iteratively performs a sequence of requests to different name servers. Since this scheme loads the client with quite complex work, it is rarely used.

The second option implements a recursive procedure:

The DNS client queries the local DNS server, that is, the server that services the subdomain to which the client name belongs;

if the local DNS server knows the answer, then it immediately returns it to the client; this may correspond to the case where the requested name is in the same subdomain as the client's name, and may also correspond to the case where the server has already learned this match for another client and stored it in its cache;

if the local server does not know the answer, then it performs iterative requests to the root server, etc., in the same way as the client did in the first option; Having received the answer, it transmits it to the client, which all this time was simply waiting for it from its local DNS server.

In this scheme, the client delegates work to its server, hence the scheme is called indirect or recursive. Almost all DNS clients use a recursive procedure.

To speed up the search for IP addresses, DNS servers widely use the procedure of caching responses passing through them. To allow the DNS service to quickly respond to changes occurring in the network, responses are cached for a certain amount of time - usually from several hours to several days.

The TCP/IP stack uses three types of addresses: local (also called hardware), IP addresses, and symbolic domain names. All these types of addresses are assigned to the nodes of the composite network independently of each other.

An IP address is 4 bytes long and consists of a network number and a host number. To determine the boundary separating the network number from the node number, two approaches are implemented. The first is based on the concept of address class, the second is based on the use of masks.

The address class is determined by the values ​​of the first few bits of the address. Class A addresses allocate one byte for the network number, and the remaining three bytes for the node number, so they are used in the largest networks. Class addresses are more suitable for small networks WITH, in which the network number takes three bytes, and only one byte can be used to number nodes. Class B addresses occupy an intermediate position.

Another way to determine which part of the address is the network number and which part is the host number is based on the use of a mask. The mask is a number that is used in conjunction with an IP address; The binary mask entry contains ones in those bits that should be interpreted as a network number in the IP address.

Network numbers are assigned either centrally, if the network is part of the Internet, or randomly, if the network operates autonomously.

The process of distributing IP addresses among network nodes can be automated using the DHCP protocol.

Establishing a correspondence between an IP address and a hardware address (most often a MAC address) is carried out by the ARP address resolution protocol, which looks through ARP tables for this purpose. If the required address is not available, a broadcast ARP request is made.

The TCP/IP stack uses a domain symbolic naming system, which has a hierarchical tree structure that allows an arbitrary number of components to be used in a name. A collection of names in which several of the higher components coincide form a name domain. Domain names are assigned centrally if the network is part of the Internet, otherwise - locally.

The correspondence between domain names and IP addresses can be established either by means of the local host using the hosts file, or by using a centralized DNS service based on a distributed database of “domain name - IP address” mappings.

The IP protocol solves the problem of delivering messages between nodes of a composite network. The IP protocol is a connectionless protocol, so it does not provide any guarantee of reliable message delivery. All issues of ensuring the reliability of data delivery in a composite network in the TCP/IP stack are resolved by the TCP protocol, based on the establishment of logical connections between interacting processes.

An IP packet consists of a header and a data field. The maximum packet length is 65,535 bytes. The header is usually 20 bytes long and contains information about the network addresses of the sender and recipient, fragmentation parameters, packet lifetime, checksum and some others. The data field of an IP packet contains higher layer messages, such as TCP or UDP.

The type of IP routing table depends on the specific implementation of the router, but despite quite strong external differences, the tables of all types of routers contain all the key fields necessary to perform routing.

There are several sources that supply routing table entries. First, upon initialization, the TCP/IP stack software writes into a table entries for directly connected networks and default routers, as well as entries for special addresses such as 127.0.0.0. Second, the administrator manually enters static entries about specific routes or the default router. Third, routing protocols automatically enter into a table dynamic records of available routes.

Masks are an effective means of structuring IP networks. Masks allow you to divide one network into several subnets. Equal-length masks are used to divide a network into subnets of equal size, and variable-length masks are used to divide a network into subnets of different sizes. The use of masks modifies the routing algorithm; therefore, in this case, special requirements are imposed on routing protocols in the network, on the technical characteristics of routers and their configuration procedures.

A significant role in the future of IP networks will be played by classless inter-domain routing (CIDR) technology, which solves two main problems. The first is a more economical use of address space - thanks to CIDR, service providers are able to “cut” blocks of different sizes from the address space allocated to them in strict accordance with the requirements of each client. The second goal is to reduce the number of routing table entries by aggregating routes - one routing table entry can represent a large number of networks with a common prefix.

An important feature of the IP protocol that distinguishes it from other network protocols is its ability to dynamically fragment packets as they are transmitted between networks with different MTUs. This property has largely contributed to the fact that the IP protocol has been able to occupy a dominant position in complex composite networks.

Internet is a collection of local networks of computers located around the world that communicate with each other according to uniform rules called protocols.

In order not to remember the numerical address of a computer, the DNS system was created. Domain Name System or DNS (Domain Names System), associates names like the digital addresses (185.12.92.137) that computers use to communicate with each other.

In order for your website with your domain name to work, you must specify the DNS servers on which it will be “recorded” on which server (hosting) your website is located. DNS servers look like:

Ns1.yourhosting.ru
ns2.yourhosting.ru

There are three ways to configure DNS:

1. DNS registrar. In this case, you will need to fully configure the DNS zone as in the third option.
2. Hosting provider DNS. In this case, all preliminary DNS configuration sufficient for the normal operation of your site will be done by the hosting provider.
3. Third party DNS. You can specify DNS hosting in general on a third-party DNS server, for example, Yandex-DNS.

How to specify (change) DNS servers for a domain?

To specify/change the DNS server for a domain, you need to:

1. register with a domain name registrar;
2. Find the required domain and select there "DNS Server Management / Delegation"
3. In the form that opens, specify the required DNS servers (IP may not be specified). or check the box "Use the registrar's DNS server".
4. Click on the "Save" button.

Information about your changes will be available for a period from several minutes to 72 hours. Therefore, at first it is possible that the DNS servers will be old. This does not depend on the registrar or hosting provider. All you have to do is wait.

Setting up DNS records.

To add/change records on the DNS server, you need to do the following:

Example of adding records to DNS:

Let's assume you have registered the domain mydomain.ru and the IP address of the web server on which the site will be located - 195.128.128.26. In this case, you will need to create at least two records of type "A" for your domain (to link mydomain.ru and www.mydomain.ru with the address 195.128.128.26). To do this, in the form for adding "A" records, in the "Subdomain Name" field, specify "@" for the first record and "www" for the second record, and in the "Data" field, specify 195.128.128.26 (for both records).

To forward all subdomains to an IP address, you need to specify * as the “Subdomain Name”

Example 2: You want the mail.mydomain.ru address to point to the same host as the relay.highway.ru address. To do this, you need to specify "mail" in the "Subdomain Name" field, select "Record Type" CNAME, and specify "relay.highway.ru." in the "Data" field.

Example of DNS records for the mydomain.ru zone:

@ A 195.161.114.80 @ MX 10 relay.highway.ru. www A 195.161.114.80 ctrl CNAME ctrl.muse.highway.ru. ftp CNAME ftp.muse.highway.ru. mail CNAME relay.highway.ru. ssh CNAME ssh.muse.highway.ru.

Instructions for changing DNS servers

1. If you specify DNS servers for the RU, SU, RF domain that are located in the same domain (i.e., “your” DNS), for example, for the domain testsite.ru you specify the DNS server ns1.testsite.ru And ns2.testsite.ru, That Necessarily You must specify its IP address for each DNS server.
2. If you specify a DNS server for any domain that is located in another domain, for example, for the domain testsite.ru you specify the DNS server ns1.abrakadabra.ru And ns2.abrakadabra.ru, then specify IP addresses for each DNS server no need.
3. The IP addresses of DNS servers (if necessary, see above) for the RU, SU, RF domains must differ by at least one digit! Same IP for all DNS is not allowed.
4. For international domains (com, net, org, info, etc.), the DNS servers that you specify for the domain must be Necessarily registered in the international NSI Registry database. If they are not registered there, then they cannot be indicated. For international domains, IP addresses for DNS servers do not need to be specified. They are indicated when registering DNS in the NSI Registry database

How to attach a domain to an IP address?

In order to attach a domain to an IP address, you need to:

Now you need to wait until the changes take effect and your site will open from this IP address. This may take up to 72 hours.

How long does it take for DNS changes to take place?

Changes to DNS are made instantly. But due to the fact that providers cache DNS, the process of changing DNS around the world can take anywhere from a few minutes to 72 hours.

What DNS servers can be used to access the Internet?

To obtain an IP address from a domain name, you can use the following DNS servers:

8.8.8.8 4.4.4.4

77.88.8.8 77.88.8.1

Read more about Yandex DNS and how to protect yourself from malicious sites using DNS at dns.yandex.ru

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When representatives of two companies exchange business cards during business communication, the email address and the name of the company’s corporate Web site will be indicated on them (the business cards). At the same time, you can also hear how the interlocutors exchange “Internet addresses” (“electronic addresses”) of companies. In all of the above cases, one way or another we are talking about the use of domain names.

In an email address, formally, the domain name can be considered what is written after the commercial at symbol - “@”. For example, in [email protected] The domain name of the mail node is test.ru.

The Web site name is the domain name of that site. For example, Microsoft's Web site has the domain name Microsoft.com.

In most cases, when searching for information on the Internet, we search through domain names or follow links whose notation again uses domain names.

Quite often, along with the phrase “Internet address,” “domain address” is used. Generally speaking, neither one nor the other concept exists in TCP/IP networks. There is numeric addressing, which relies on IP addresses (a group of 4 numbers separated by a ".") and the Internet service Domain Name System (DNS).

Numerical addressing is convenient for computer processing of routing tables, but is completely (here we are exaggerating somewhat) not acceptable for human use. It is much more difficult to remember sets of numbers than mnemonic meaningful names.

However, connections to exchange information on the Internet are established using IP addresses. Symbolic names of the domain name system are a service that helps to find the IP addresses of network nodes necessary to establish a connection.

However, for many users, it is the domain name that acts as the address of an information resource. In the practice of administering local networks, there are often situations when users complain to the network administrator about the inaccessibility of a particular site or long loading times of pages. The reason may lie not in the fact that the network segment has lost connection with the rest of the network, but in poor DNS performance - no IP address, no connection.

DNS hasn't been around since the birth of TCP/IP networks. At first, to facilitate interaction with remote information resources on the Internet, tables of correspondence between numeric addresses and machine names began to be used.

Modern operating systems also support tables of correspondence between the IP address and the machine name (more precisely, the host) - these are files named hosts. If we are talking about a Unix-type system, then this file is located in the /etc directory and looks like this:

127.0.0.1 localhost
144.206.130.137 polyn Polyn polyn.net.kiae.su polyn.kiae.su
144.206.160.32 polyn Polyn polyn.net.kiae.su polyn.kiae.su
144.206.160.40 apollo Apollo www.polyn.kiae.su

To access a machine, a user can use both the machine’s IP address and its name or alias. As can be seen from the example, there can be many synonyms, and, in addition, the same name can be specified for different IP addresses.

Let us remind you once again that you cannot gain any access to the resource using the mnemonic name itself. The procedure for using a name is as follows:

• first, the IP address is found in the hosts file by name,
• then a connection to a remote information resource is established using the IP address.

The calls below are similar in their effect - initiating a telnet session with the Apollo machine:

telnet 144.206.160.40

telnet www.polyn.kiae.su

In local networks, hosts files are still used quite successfully. Almost all operating systems from various Unix clones to the latest versions of Windows support this system of mapping IP addresses to host names.

However, this way of using symbolic names was fine as long as the Internet was small. As the Web grew, it became difficult to maintain large, consistent lists of names on each computer. The main problem was not even the size of the match list, but the synchronization of its contents. In order to solve this problem, DNS was invented.

DNS was described by Paul Mockapetris in 1984 in two documents: RFC-882 and RFC-883 (These documents were later replaced by RFC-1034 and RFC-1035). Paul Mockapetris also wrote the DNS implementation - the JEEVES program for the Top-20 OS. It is this that RFC-1031 suggests that administrators of machines running the Tops-20 OS of the MILNET network switch to. We will not go into detail about the contents of RFC-1034 and RFC-1035. Let's limit ourselves to just the basic concepts.

The role of the name (domain name) in the connection establishment process remains the same. This means that the main thing it is needed for is obtaining an IP address. Consistent with this role, any DNS implementation is an application process that runs on top of the TCP/IP internetworking protocol stack. Thus, the IP address remains the basic element of addressing in TCP/IP networks, and domain naming (domain name system) serves as an auxiliary service.

The domain name system is built on a hierarchical principle. More precisely, according to the principle of sets nested within each other. The root of the system is called "root" (literally translated as "root") and is not designated in any way (has an empty name according to RFC-1034).

It is often written that the designation of the root domain is the "." symbol, but this is not so, the dot is a separator for the components of the domain name, and since Since the root domain does not have a designation, the fully qualified domain name ends with a period. However, the "." is quite firmly established in the literature as a designation for the root domain. This is partly due to the fact that in the configuration files of DNS servers, this particular character is indicated in the domain name field (NAME field according to RFC-1035) in resource description records when it comes to the root domain.

The root is the entire set of Internet hosts. This set is divided into first-level or top-level domains (top-level or TLD). The ru domain, for example, corresponds to many hosts on the Russian part of the Internet. Top-level domains are split into smaller domains, for example, corporate ones.

In the 80s, the first first-level domains (top-level) were defined: gov, mil, edu, com, net. Later, when the network crossed the national borders of the United States, national domains like: uk, jp, au, ch, etc. appeared. The su domain was also allocated for the USSR. After 1991, when the republics of the Union became sovereign, many of them received their own domains: ua, ru, la, li, etc.

However, the Internet is not the USSR, and you cannot simply throw out the su domain from the domain name system. Domain names are used to build email addresses and access to many other Internet information resources. Therefore, it turned out to be much easier to introduce a new domain to an existing one than to replace it.

To be more precise, no provider currently allocates (delegates) new names with the su extension. However, many people want to resume the process of domain delegation in the SU zone.

The list of first-level domains (top-level) and their types can be found, for example, in the material “General information about the domain name system” at https://site/domains/review.html.

As already mentioned, after top-level domains there are domains that define either regions (msk) or organizations (kiae). Nowadays, almost any organization can get its own second-level domain. To do this, you need to send an application to the provider and receive a registration notification (see "How to get a domain").

Part of the domain naming tree can be represented as follows:

Fig.1. An example of part of a domain name tree.

The root of the tree does not have a label name. Therefore it is designated as "". The remaining nodes of the tree have labels. Each node corresponds to either a domain or a host. A host in this tree is understood as a leaf, i.e. a node below which there are no other nodes.

You can name a host either by a partial name or by a full name. A fully qualified host name is a name that lists, from left to right, the names of all intermediate nodes between the leaf and the root of the domain naming tree, starting with the leaf name and ending with the root, for example:

polyn.net.kiae.su.

A partial name is a name that lists not all, but only part of the host names, for example:

polyn
apollo.polyn
quest.polyn.kiae

Please note that partial (incomplete) names do not have a dot at the end of the name. In real life, domain name system software expands unqualified names into full names before contacting domain name servers for an IP address.

The word "Host" is not fully synonymous with the name of the computer, as is often simplified. Firstly, a computer can have many IP addresses, each of which can be associated with one or more domain names. Secondly, one domain name can be associated with several different IP addresses, which, in turn, can be assigned to different computers.

Once again, note that the naming goes from left to right, from the minimum host name (from the leaf) to the root domain name. Let's look at, for example, the full domain name demin.polyn.kiae.su. The host name is demin, the name of the domain to which this host belongs is polyn, the name of the domain that covers the polyn domain, i.e. is broader in relation to polyn, - kiae, in turn, the latter (kiae) is part of the su domain.

The name polyn.kiae.su is already a domain name. It is understood as the name of many hosts that have polyn.kiae.su in their name. Generally speaking, the name polyn.kiae.su can also have a specific IP address assigned to it. In this case, in addition to the domain name, this name will also denote the host name. This technique is often used to provide short and meaningful addresses in an email system.

Host and domain names are separated from each other in this notation by a "." character. The fully qualified domain name must end with a "." character, because the last dot separates the empty root domain name from the top-level domain name. Often in the literature and in applications, this point is omitted when writing a domain name, using the unqualified domain name notation, even when all node names from the leaf to the root of the domain name are listed.

It should be borne in mind that in real life domain names are rather bizarrely mapped to IP addresses, and even more so to real physical objects (computers, routers, switches, printers, etc.) that are connected to the network.

A computer physically installed and connected to the Network in distant America can quite easily have a name from a Russian corporate domain, for example, chalajva.ru, and vice versa, a computer or router in the Russian segment can have a name from the com domain. The latter, by the way, is much more common.

Moreover, the same computer can have multiple domain names. It is possible that several IP addresses can be assigned to one domain name, which are actually assigned to different servers serving the same type of requests.
Thus, the mapping between domain names and IP addresses within the domain name system is not one-to-one, but is many-to-many.

The last few remarks were intended to draw the reader's attention to the fact that the hierarchy of the domain name system is strictly observed only in the names themselves and reflects only the nesting of naming and the areas of responsibility of the administrators of the corresponding domains.

We should also mention canonical domain names. This concept is found in the context of describing the configurations of subdomains and areas of responsibility of individual domain name servers. From the point of view of the domain tree, domain names are not divided into canonical and non-canonical, but from the point of view of administrators, servers and email systems, such a division is essential. A canonical name is a name that is explicitly associated with an IP address, and which itself is explicitly associated with an IP address. A non-canonical name is a synonym for a canonical name. See "setting up BIND" for more details.

The most popular implementation of the domain name system is the Berkeley Internet Name Domain (BIND). But this implementation is not the only one. So, Windows NT 4.0 has its own domain name server that supports the DNS specification.

However, it is advisable even for Windows administrators to know the operating principles and rules for configuring BIND, because It is this software that maintains the domain name system from the root to the TLD (Top Level Domain).

1. P. Mockapetris. RFC-1034. DOMAIN NAMES - CONCEPTS AND FACILITIES. ISI, 1987. (http://www.ietf.org/rfc/rfc1034.txt?number=1034)
2. P. Mockapetris. RFC-1035. DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION. ISI, 1987. (http://www.ietf.org/rfc/rfc1035.txt?number=1035)
3. W. Lazear. RFC-1031. MILNET NAME DOMAIN TRANSITION. 1987. (http://www.ietf.org/rfc/rfc1031.txt?number=1031)
4. Albitz P., Lee K.. DNS and BIND. - Per. from English - St. Petersburg: Symbol-Plus, 2002. - 696 p.

1. http://www.dns.net/dnsrd/docs/

In this material we will examine two large topics at once. Let's learn how to determine the DNS and IP address parameters for our home Internet connection. And let’s get acquainted with the tools that will allow you to find out the same parameters, only for a site operating on the Internet.

What is it used for

Essentially, we will only work with the IP address. The only difference is that it will be found for different network nodes. After all, the DNS server address is its IP. By the way, there may be several of them - you need to remember this. Let's remember the theoretical part. An IP address is a unique identifier of a node in a network whose operation is based on the IP protocol. These include almost all modern networks, from the smallest to the Internet. An IP address is necessary to ensure normal data transfer via the IP protocol. With its help, an addressing mechanism is implemented, thanks to which it becomes clear where and what data needs to be transferred.

You will need:

How to find out the IP and DNS addresses of your home computer

There are several ways to do this. Let's look at the main ones.

ipconfig utility

It is included in all Microsoft Windows operating systems. Press Win+R, then type cmd and press Enter. The command line will launch. Here you need to type

ipconfig /all

And click Enter. All information regarding connected network adapters and created connections will be displayed. We are interested in the one that is responsible for connecting to the Internet. You need to know its name. You can view it in the control panel, in the "Network Center" section. Since the computer I'm working on uses wireless Internet access, we need to select a Wi-Fi adapter from the list. It's called "Wireless LAN Adapter...". All information is illustrated in the figure above. In the list of parameters we are interested in two values ​​- IPv4 address and DNS servers. These are the parameters we were looking for.

View settings in connection properties

You can go the other way and look at the settings of the desired connection directly. To do this, we go to "Control Panel - Network Control Center". Then go to "Change adapter settings". Select the one you need from the list, call up the context menu for it, and click “Status”. Then the "Details" button.
As you can see in the picture, the same data is displayed here.

Online services

There are many simple services on the Internet that allow you to check your IP address. The easiest way to do this is on Yandex. Go to

Type the query "How to find out your ip". Anything similar can be used. And do a search. The information you need will come first.
As you can see in the picture, Yandex kindly told us our address. But it is different from the one we got in the previous steps. The thing is that we connect to the Internet via a Wi-Fi router. The connection to the provider is configured on it. In the first steps we saw the local IP of the adapter. Yandex showed us the external one, the one assigned by the provider.

Online site parameters

If you are creating and promoting websites, you may need to find out the IP address of the server on which your website is located and the DNS of the domain registrar.

Tracert utility

Open the command line again. Now we type:

tracert %your-site%

Substitute the desired URL address into the command.
As a result, you will see the server address.

2ip

You can use the online service 2ip. Both tools are available here. The first one is for checking the IP address:

http://2ip.ru/lookup/

The second one is to determine the DNS server

http://2ip.ru/dig/

Enter the desired URL into the form and carry out the analysis. DNS addresses are indicated in the "NS" (name server) lines.

Video for the article:

Conclusion

The methods discussed above will allow you to determine the necessary data. IP and DNS are most often needed by network administrators. But it’s also a good idea for ordinary users to know the methods by which these parameters can be determined.

MAC address. Subnet mask. Internet via Bluetooth.

Why look for information on other sites if everything is collected here?

techprofi.com

Why do you need DNS?

The DNS server can be the cause of many problems with the Internet and websites. If most users already know and understand what a computer’s IP address is (at least approximately), then with a DNS address everything is somewhat more complicated, because for many it is something completely incomprehensible and unknown. In fact, everything is just as simple here. In this article we will take a closer look at what DNS is and how to find it out. Let's figure it out. Go!

Connecting to a DNS server

The abbreviation DNS means Domain Name System or domain name system - in Russian. Essentially, it is a global key-value store. Every server in any part of the world will provide the required value for the corresponding key. If the server does not know a specific key, it will request it from another. In other words, an IP address is requested by hostname.

The domain name system plays a huge role in the operation of the Internet. In order for a connection to a node to occur, information about the IP address is needed. For any person, remembering a name is much easier than a sequence of numbers. Imagine if every time you needed to visit a website, you entered its IP address. By the way, this is exactly how everything happened at the dawn of Internet technology, when it just began to spread.

The Domain Name System has a hierarchy of servers that matches the hierarchy of zones. Each of them is supported by a so-called authoritative DNS server, which contains all the information about the domain. It is necessary to understand that an IP address and a name are not the same thing, since an IP can have an unlimited number of names, which, in turn, allows the user to view an unlimited number of sites on one device. This principle also works in the opposite direction.

If you want to find out your computer's DNS, there are several ways to do it. The first one is the fastest and easiest. First, open the command line (to do this, use the Win + R key combination and write cmd in the input field, then click on the “OK” button), and then run the ipconfig / all command. This way you will receive the necessary network information as quickly as possible.

ipconfig/all command

The second option is through the Windows interface. Open Control Panel. Select the "Network Connections" section. In the window that appears, right-click on the active connection and click “Properties”. Then you need to click the “Properties” button again. After this, a window will appear with information about IP and DNS addresses.

Information about IP and DNS addresses

Now you know what DNS is, how to find it and what it means. As you can see, everything is actually quite simple. Write in the comments whether this article helped you understand the issue, and ask if anything remains unclear.

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How to find out the DNS server address

To open any page on the global network, you need to type its domain name in the address bar of your Internet browser. Ordinary users call it the name of the Internet page.

All domains on the World Wide Web have a specific digital IP address. Lists of website names and their IPs are stored on DNS servers.

Below are detailed guides on how to find out DNS not only for connecting a PC to the Internet, but also for the interaction of a domain and hosting for some Internet page.

Determination methods

To determine your DNS or if you need to identify your DNS provider, there are various methods for this. It is recommended to use the following 3 effective techniques:

1. Using command line capabilities (CL);
2. Through analysis of network properties;
3. Contact your telecom service provider.

It is advisable to use methods No. 1 and No. 2 to determine DNS if there is a good connection to the global network and it is functioning normally. The last method can be used in the absence of an Internet connection.

1. Using command line functionality

So, users who are wondering how to find out their own or their DNS provider need to perform the following sequential steps:

1) Through “Start”, launch “KS”;

2) In the black window that appears, type “ipconfig/all” and then click “Enter”;

3) Detailed information will appear;

Among the many additional data, the user will have access to information about DNS servers.

2. Analysis and adjustment of connection parameters

To solve the problem, by analyzing the network properties, you need to use the tools from the control panel.

The sequence of actions is as follows:

1) Through the “Start” menu, open “Control Panel” and then, if XP OS is installed on the PC, then you should enter “network connections”, and if “Seven”, then go to the “Network Control Center” tab and open “ Change adapter settings";

3) Open a tab with a list of “Internet Protocol (TCP/IP)”, where the current server names are written, which can be adjusted and the preferred and alternative DNS addresses entered;

4) If you make any adjustments, you must save the changes before closing the window.

3. Determine by contacting your communication service provider

This can be quickly done using the following three methods:

1) Open the official resource of the Internet provider and read the information provided from its page;

2) Call technical support;

3) Generate and send a request to call a specialist to the location of the user’s computer.

Alternative option through online services

There are a significant number of services on the Internet that allow you to quickly solve the problem, for example, through Yandex. You just need to type “How to find out your ip” or other required query in the search bar and click “Find”.

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How to find out the DNS address of an Internet resource?

To get to a website, you need to enter its domain name in the browser. Often users call it the name of the site. Each domain on the Internet has its own IP address. Relatively speaking, there are special lists of domain names and their corresponding addresses. As you know, any information must have a specific storage location. The same applies to the above matching lists. To store them, special servers called DNS (Domain Name System) are used. It is the work of DNS servers that you use every day, but do not notice it.

Note that the domain name system was first developed back in 1983, and in 1990 it was rewritten in some way. The world should be grateful to Paul McPartison for his development. It was he who came up with the idea of ​​keeping a record of domain names, like a notebook with phone numbers. At his request, three promising student enthusiasts slightly modified the code. The system obtained in 1990 became the most popular and is still used today.

There is such a thing as a DNS name. It must be specified when creating a domain and carrying out the process of linking it to any hosting.

In some cases, you may need to find out the DNS, IP, or domain name of a resource. For the search to be successful, the user must have some knowledge and skills. Let's try to figure out how to find out DNS. If you have information about the domain name and have minimal Internet skills, then the task of finding out the DNS should not be a problem for you. There are quite a few so-called whois services on the Internet.

Any such site contains information on how to find out DNS by domain name. To do this, you will need to go to the request page, enter the required domain name and start the scanning process. The result of the site will be the display of the information you are interested in. As an example, you can try entering the domain name of one of the well-known search engines. As a result, the addresses of DNS servers will be obtained, which usually look like this: "ns1..., ns2..., ns3..."

In some cases, you need to know your DNS provider. How to find out your ISP's DNS? To do this, you will need to open the command line, enter the command “ipconfig /all” and confirm its execution. In the list of displayed information there will be a “DNS servers” field, in it you will find comprehensive information that you needed to find. In order to open the command line, you need to go to the "Start" menu, then select the "Run" menu and enter the command "cmd" in the line that appears. After pressing the "Enter" button, a black window with inscriptions will appear - this is the command line window.

If for some reason you need to find out the IP address of an Internet resource, the easiest way to do this is to use the “ping” command. We open the command line that is already familiar to us and enter the necessary command: “Ping.” After confirming the entry, the exchange of data packets with the Internet site you entered will begin. In the first line you will see the IP address you need.

We have tried to describe the simplest and fastest methods for determining a DNS address and hope that the question “how to find out DNS?” is now closed for you.

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How to determine the DNS server address?

Have you ever tried to restore your Internet connection yourself? If yes, then you would be a little familiar with DNS terms, DNS server address, etc. For the benefit of those who feel a little alienated by all these terms, it's worth starting at the beginning.

The full form of DNS is Domain Name System. Without going into too much technological detail, its significance in the field of Internet technology is explained below. The importance of the DNS server address.

DNS servers maintain a log of every website on the Internet. Each website is associated with a unique IP (Internet Protocol) address in the format "xxx.xxx.xxx.xxx". To view, for example, the IP address www.comerartadvisory.com, you should go to the numbers 209.18.68.131. Now the problem is that DNS servers are capable of tracking each website based on its IP address and not its domain name. However, it is much easier for a person to remember a site by its name rather than by its numerical value. Naturally, there must be some way around this problem.

When, as a user, you type "www.comerartadvisory.com" into the address bar of your web browser, your computer sends a query to the nearest DNS server, which displays the string "www.comerartadvisory.com" with the corresponding numeric IP address. Once this is completed successfully, the DNS server redirects your computer to that specific IP address and then the web page opens in the web browser. With over 5 billion websites on the Internet, one can very well imagine the size of the IP address directory and the speed at which a DNS server must operate to provide fast and efficient results.

How to determine your computer's DNS server address

The easiest and fastest way to find your computer's DNS server address is through the command line.

You can do this through the following steps:

Click the "Start" button in the lower left corner of your computer screen.

DNS - what is it and what is it used for?

The Internet is a countless number of physical devices (servers, computers, tablets, etc.) connected to each other in a network. Any website on the Internet is actually located on a physical device. Each device has its own unique number - an IP address of the form 123.123.123.123.

To get to the site, you need to know the IP address of the device on which the site is located. Now imagine how many sites you visit per day and how many numbers you would have to remember. Of course, this is unrealistic. Therefore, for the convenience of working on the Internet, a domain name system was created in the 80s - DNS(Domain Name System). Its meaning is that each digital IP address is assigned a clear alphabetic name (domain). When you enter a domain name in your browser, DNS servers convert it to an IP address..58.116.30.

What are DNS servers for?

The Domain Name Service works thanks to DNS servers. It is these vital “programs” that store correspondence tables of the form “domain name” - “IP address”. In addition, DNS servers serve to store domain resource records: There are a huge number of DNS servers on the Internet, each performing its own function in the overall system. The Domain Name System service is necessary so that we can easily find our favorite sites without remembering strings of numbers.

So, you enter the name of the site in the address bar and press Enter. In those very seconds before the site is displayed on your screen, DNS servers work without sparing themselves. Let's see what DNS servers do. Follow the arrows.

1. 1.

   After receiving a domain name from you, the computer contacts the DNS servers of your Internet service provider ( arrow 1). The provider's DNS servers look for the IP address in the cache. If found, they give you an IP address ( arrow 6) and using this IP address your computer accesses the server on which the site is hosted ( arrow 7).The site is displayed on the computer screen. That's all :)

2. 2.

   If the “domain-IP address” pair is not in the cache of the ISP’s DNS servers, the provider’s DNS server sends a request to the root DNS servers ( arrow 2). There are only a few such servers around the world, and the information on them is updated several times a day. Root servers report the addresses of the domain's DNS servers ( arrow 3). The ones that need to be registered for a domain after registration and which store all the current information about the domain (IP address, resource records, etc.).

3. 3.

   Having received the addresses of the domain DNS servers, the provider makes a request to one of them ( arrow 4), receives the long-awaited IP address in response ( arrow 5), stores it in the cache (so that you don’t have to contact the root DNS server every time) and finally reports this IP address to your browser ( arrow 6).

4. 4.

   And only now the satisfied browser uses the IP address to contact the server on which the site is located ( arrow 7), and displays the site for you on your computer screen ( arrow 8).

Why register DNS servers for a domain?

Let's say you have registered a domain. So far, no one except you knows about this. In order for the Internet to know about the existence of your domain, you need to select and register DNS servers for the domain. They will tell other Internet DNS servers about your domain. So let's remember: registered a domain - specify DNS servers!

DNS servers are most often prescribed in pairs. One of the DNS is the primary, and the remaining servers, which can be from 1 to 12 for each domain, are called secondary. This is done for better fault tolerance: if one DNS server fails, the domain and website will continue to function.

Why don't domains start working right away?

The ISP's DNS servers are updated once a day (). If you have just registered or changed DNS servers, you will have to wait 24 hours. Changing the DNS server is fraught with the temporary absence of a working website. After updating the DNS, the site will become accessible. If the site does not work, here are the instructions to help you: .