Restrictions when choosing and registering a new domain. Domain - what is it and why is it needed

If you are starting a business and want to make it profitable, you simply cannot do without a quality selling web resource. Once you've come up with a great domain name for your site, and it's time to register in a domain zone, you need to choose from dozens of suggested ones. In case you don't know what is the difference between info.kz, com.kz and org.kz which is best for your web resource - .ru, .biz or .com, whether there is any difference between all domain zones at all, this article will be extremely useful for you.

1. What does “domain zone” and “domain of the first, second and third levels” mean?

Surely you have come across the concept of “first (second, third) level domain” more than once. To make it easier to explain what this means, consider an example: www.yoursite.com - this is a second-level domain, where the first-level domain (and this is the domain zone) is the ending after the dot - com. When adding another word (for example, yoursite.com.ua) results in a third-level domain (subdomain). Fourth-level domains are formed according to the same principle (for example, images.yoursite.com.ua), but they are extremely rare.

2. What are the domain zones?

The domain zone determines whether the domain of the second (third, fourth) level belongs to the country or type of activity of the site. In this regard, there are:

International domain zones (.info, .com, .biz, etc.)

• .com- domain general purpose(common). It was originally intended for commercial (commercial) organizations, but did not have the appropriate restrictions and eventually lost its purpose;
• .net- as a rule, it is chosen by organizations providing network services;
• .biz- earlier its analogue was the .com zone (before it lost its purpose). Today, .biz sites are chosen by any commercial organization;
• .info- suitable for reference and information portals, blogs and home pages;
• .org- Designed for websites of non-profit organizations.

Thematic domain zones (.tv, .fm, etc.)

Their choice is due to the thematic focus of the web resource:

• .tv— designed for websites of TV channels, TV broadcasts, etc.;
• .fm- in this zone, it is customary to register web resources of radio stations;
• .travel- designed for companies operating in the tourism sector.

stick simple rule:register a domain in the thematic zone corresponding to its purpose. For example, if you are creating informational portal, choose a zone .info, and for the site of a commercial organization, it will be an excellent option .biz.

Regional and sub-regional domain zones(.ru, .by, .de, etc. - indicate belonging to the country, .spb.ru, kiev.ua - to the region) :

• .ru, .rf- Russia;
• .ua- Ukraine;
• .by— Belarus;
• .kz- Kazakhstan;
• .de— Germany;
• .fr— France;
• .su- (Soviet Union) - the countries of the former USSR (today it is used mainly by the CIS and the Baltic states).
• .eu— European Union;
• .msk.ru- Moscow;
• .spb.ru- St. Petersburg.

If the site will be visited mainly by people from Belarus or the organization operates in this country, then the best option for the web resource address there will be a zone.by. If you want to emphasize belonging to a particular city, for example, St. Petersburg, register in the spb.ru zone. For a company whose activities are focused on people from Russia, excellent choice there will be a zone.rf. Doubt whether to register in the domain zone.рф? Be sure to read our article on this topic.

Regional-thematic domain zones

• .edu.ru- can be used to create websites educational institutions Russia;
• .pp.ua- ("pp" - "private person" or "private page") - great for personal pages and blogs;
• .co.ua- is an analogue of the Ukrainian domain.com.ua, belongs to the category of general purpose and is not limited to special requirements.

3. Can I choose any domain zone?

In general, yes. However, when choosing, it should be borne in mind that some first-level domains require compliance with the declared topic for registration, while others are available to everyone. Therefore, it is better to register a site in a zone that will help users understand what the resource is about.

4. International or regional first level domain?

To resolve this issue follow simple rule: if the audience or activity of your company is not limited to one country, you can register a domain in international zone, for example, .biz. In the event that you want to present the project to the population of your state, it is better to use the zone of your country, for example.kz or.org.kz.

5. How to choose a domain for a highly specialized site?

When creating a site with a narrowly focused theme, for example, gardening, you can search for a suitable domain zone on the Internet. It is very easy to do this. Type in search engine keywords("gardening") and see which top-level domains have sites on the first two pages.

We hope that in this article you have found all the answers to your questions on this topic. If you are the owner of a free site to the site and it looks like yoursite.site , we recommend that you buy a second-level domain that will make your resource in the eyes potential clients more representative.

Create a site to site in 5 minutes, choose the right domain and promote your business online!

We released new book"Content Marketing in social networks: How to get into the head of subscribers and fall in love with your brand.

Domain is the hierarchical name of the site.

A domain can be compared to a residential address. To understand where a person lives, you need to know the city, street, house and apartment number. Same with the site. To enter, you need to know his address.

Domains were invented to give a face to a site's IP address. After all, remembering addresses like 146.264.74.01 is simply impossible.

Consists of letters, numbers and hyphens. Its length can be from 2 to 63 characters.

Domain zones and their types

These are the addresses in certain area. Domain zones can be of two types:
National zones define a country. For example, Russia - .ru, Ukraine - .ua, Germany - .de, USA - .us, etc.
Zones common use are for everyone. For example:

• .com - for commercial projects;
• .org - for non-commercial sites of various organizations;
• .info - for all information projects;
• .biz - only commercial organizations, .net - for projects related to the Internet;
• .edu - for educational institutions and projects, .name for personal sites, etc.

Website Domain Name Transformation

The IP address looks like 123.123.123.123. It is used to identify computers on the network, to address data - to connect computers to each other. Similar to how you save phone numbers, you can start notebook or a telephone directory for IP addresses. Role telephone directory on the Internet perform - the domain name system. Without it, the functioning of the Internet would be impossible.

A DNS server is a program that converts a domain name to a digital IP address and vice versa. These servers have extensive tables in memory that map each domain name to an IP address. In order to better understand this, let's look at an illustrative example:

DNS gives information to computers how to find each other over the Internet. When you type an address in your browser, your ISP checks it through the domain name server to know where to send your request: http://www.domain.ru ---> check in DNS ---> DNS reports the address of domain.ru = 192.168.0.1 ---> You are getting the content of the site.

Let's say the client requested the address "www. Organization. city. the country". Searching for information on a domain name occurs as follows: the client asks its server. If he belongs to this zone, he will answer where it all ends. It also asks for the root server. The other cannot answer because he does not know; but he knows that the “country” is responsible for the zone. The user of the “country” zone also cannot answer, but knows that he needs to ask the server of the “city, country” zone. That, in turn, sends a request to the user of the “organization. city. country”, which will provide the necessary information.

Understanding DNS servers can be quite important and useful for administering your project and troubleshooting DNS related issues.

Domain levels

Domains are divided into names , and third level. Moreover, if you disassemble the composition, then the reading goes from right to left, as in the figure:

Domain itself top level, marked with a dot. In common usage, it is not displayed as part of a domain name.

Top level domains

They are responsible for the territorial affiliation of the domain, the affiliation of the domain to a particular country, or the type of organization. Top-level domains are divided into several groups:

• National top-level domains. In the territory Russian Federation such names include domain zones: .RU, .SU, .РФ. International top-level domains are such domain zones as: .com, .info, .biz, .name, .org.
• New international domains top level. These domain zones are thematically focused on various areas of life and business, hobbies and everyday life, business and finance; sports and entertainment, style and beauty, professional activity.

Second level domains

This is the site's unique identifier. As an example given level you can bring the site going.ru. At the first level, the second level of the site address is registered. It is the second-level names that are common for commercial use.

Third level domains

This kind of domain is usually used to create mini-sites, or separate sections based on the main site, such as a forum. You can create an unlimited number of such domains. Examples of third-level domains are: filanco.com.ua, datahouse.com.ru.

How to register a domain

• Choose a domain zone and come up with a name.
• Check if it's free Domain name in the selected area.
• If it is free, then you can proceed to the procedure for registering an account in the server, if not already registered, and filling in the owner's data. Get ready for the fact that you will need to enter passport data. It is worth specifying real data if you do not want to lose the domain later.
• Top up your balance and pay for the registration.
• Follow the instructions of the service to complete the domain name registration process.

After registration, the domain will appear in the list on the control panel. Last step– specify a list of DNS servers, after which the process starts. If you register a domain through a hosting provider, the registration will happen automatically. Check your mail - you may receive a letter confirming registration. Check the domain owner details. They must match yours.

A domain will not be registered if it:

• Contains more than 63 characters;
• The title contains obscene language;
• Contains less than two characters, for example, a.ru;
• Contains characters other than the Latin a...z, numbers 0...9, and a hyphen - except for areas where registration of domain names in national encodings is allowed;
• Contains a double hyphen or hyphen at the beginning or end of a name.

Keep track of your balance and pay for hosting on time.

According to the guidelines (RFC-1034, RFC-1035), the domain name system consists of three main parts:

• The total set of domain names (domain name space)
• Domain name servers
• DNS Clients (Resolvers)

The set of domain names was discussed in detail in the material "Domain addressing. A bit of history and construction principles", so we will focus on the two remaining components - servers and resolvers.

The domain name system service is built according to the "client-server" scheme. The client part is an application process that requests information about the correspondence of the name to the address (or vice versa, the address of the name). This software is called a resolver. Acts as a server application program-server.

More often than not, Resolver is not any program or system component. This is a set of procedures from the application library software(for example, from the libc library), which allow a program edited with them to make queries to the domain name system and receive answers to them. These procedures access the domain name server and thus service requests from the user's applications.

A number of manufacturers operating systems, for example, Sun or SGI, offered solutions in which the resolver was a separate process, and application programs through it implemented interaction with the DNS.

Another example of the implementation of a resolver is the Nescape browsers of some versions, where a separate resolver-a process was launched to speed up the process of obtaining answers to queries to the DNS.

A self-contained resolver can also be built with BIND version 9. This is the so-called lightweight resolver. It consists of a rosolver daemon and a library for interacting with this daemon, whose procedures are linked with the application software. This resolver allows you not only to send queries to the domain name server, but also to cache matches between a domain name and an IP address.

The most commonly used domain name servers are various versions BIND (Berkeley Internet Name Domain). If the server is implemented on Windows platform, then the solution from Microsoft is used, although versions of BIND also exist for this platform.

The general scheme of interaction between the various components of the domain name system can be depicted as shown in the following figure:

Fig1. Recursive query resolver and non-recursive (iterative) procedure for resolving a domain name by a domain name server.

This name resolution scheme (setting a correspondence between a name and an IP address) is called non-recursive (iterative). How it differs from recursive we will discuss later.

Let us explain the above scheme of the non-recursive request resolution procedure:

1. The application program, through the resolver, requests an IP address by domain name from the local server (the resolver request is recursive, i.e. the resolver asks the server to find its address).
2. The local server tells the application the IP address of the requested name, while performing a non-recursive query of the domain name servers. Wherein:
   1. if the address is in its (local server's) area of ​​responsibility, it immediately reports it to the resolver,
   2. if the address is in the area of ​​responsibility of another domain name server, then it refers to the root server of the domain name system for the address of the TLD server (top-level domain server),
   3. contacts the TLD server for an address,
   4. receives from it the address of the remote server,
   5. asks a remote server for an address,
   6. receives an address from a remote server,

AT this case we have considered nesting of a second-order domain name. the host had a name similar to quest.kuku.ru or even kuku.ru.

The latter is important to understand, because corporate postal addresses type [email protected] this is exactly what is required from the application software to request the IP address of the kuku.ru host. The TLD server of the ru domain does not have information about which IP address given name matches, but at the same time he knows which server is responsible for the kuku.ru domain.

If the nesting of the domain name is greater, say, the third level (host.department.corp.ru), and this level is supported by another domain name server other than the one that supports the second nesting level, then the remote domain name server will send our local server not the host address, but the address of the new domain name server in whose area of ​​responsibility the requested name is located.

As you can see from the above diagram, obtaining information from the domain name system is a multi-step process that is not implemented instantly. AT following example shows how DNS works in practice.

When entering the remote terminal mode on the polyn.net.kiae.su computer using the command:

/usr/paul>telnet polyn.net.kiae.su

We receive in response:

/usr/paul>telnet polyn.net.kiae.su trying 144.206.130.137 ... login: .....

The line containing the IP address of the polyn.net.kiae.su computer shows that by this time the domain name was successfully resolved by the domain name server and the application program, in this case telnet, received an IP address in response to its request. Thus, after entering the command from the console, and before the IP address appeared on the monitor screen, the application program made a request to the domain name server and received a response to it.

Quite often, you may encounter a situation where, after entering a command, you have to wait a long time for a response from the remote machine, but after the first response remote computer begins to respond to commands at the same speed as your own Personal Computer. In this case, the domain name service is most likely to blame for the initial delay.

Another example of the same sort is the traceroute program. Here, the delay for requests to the domain name server is manifested in the fact that the response time from the gateways on which the ICMP packets "die" indicated in the report is small, and the delays in displaying each line of the report are quite large.

It is curious that in Windows system 3.1, some tracing programs first showed the IP address of the gateway, and only then, after allowing the "reverse" request, they replaced it with the domain name of the gateway. If the domain name service was running fast, then this change was almost imperceptible, but if the service was running slowly, then the gaps were quite significant.

You can check how "sensitive" traceroute queries are from the point of view of trace mapping to using a domain name server by setting a trace search using the server:

and without using the server:

If in the example with telnet and ftp we considered only "direct" (forward) requests to the domain name server, then in the example with traceroute we first mentioned "reverse" (reverse) requests. In a "direct" request, the application asks the domain name server for an IP address, giving it the domain name. In a "reverse" request, the application requests the domain name by providing the domain name server with an IP address.

It should be noted that the speed of resolving "forward" and "reverse" requests in general case will be different. It all depends on where the "forward" and "reverse" zones are described in the databases of the domain name servers serving the corresponding domains (forward and reverse).

We will touch on this issue in more detail when we discuss the configuration files for the named program.

However, let's return to the discussion of how the domain name system works. Actually non-recursive query considered above is only from the point of view of the server. From the resolver's point of view, the request resolution procedure is recursive, since the resolver has delegated the local domain name server to look up necessary information. According to RFC-1035, the resolver itself can query remote domain name servers and receive responses from them to its requests.

In this case, the resolver accesses the local domain name server, if it does not receive an address from it, then it queries the root domain server, obtains the address of the remote TLD server from it, queries this server, obtains the address of the remote server, queries the remote server and obtains an IP address, if he sent, the so-called "direct" request.

Fig.2. A non-recursive resolver query.

As can be seen from this diagram, the resolver itself found desired IP address. However, the general practice is that the resolver does not issue non-recursive queries, but redirects them to the local domain name server.

The local server and resolver do not execute all requests according to the specified procedure. The fact is that there is a cache that is used to store information received from a remote server in it.

The smartest resolvers, such as the Windows 2000 Server resolver and BIND 9, can maintain a cache that stores not only successfully matched name and address matches (positive response), but also the so-called "negative" responses (negative response results). ) per request. In addition, these resolvers order server address responses according to their (resolver's) preference algorithms, which are based on server response time.

Fig.3. Request resolution scheme with response caching.

If the user accesses the same network resource for a short time, then the request is not sent to the remote server, and the information is searched in the cache.

Generally speaking, the order of processing requests can be described as follows:

1. search for the answer in the local cache
2. search for an answer on the local server
3. searching for information on the web.

In this case, both the resolver and the server can have a cache.

There is a difference between a domain and a zone that can be hard to find but always worth keeping in mind. A domain is the whole set of machines that belong to the same domain name. For example, all machines that have the kiae.su postfix in their name belong to the kiae.su domain. A zone is the "zone of responsibility" of a particular domain name server, i.e. the concept of a domain is broader than the concept of a zone. If the domain is divided into subdomains, then each of them may have its own server. At the same time, the area of ​​responsibility of the server is more than high level there will be only that part of the domain description that is not delegated to other servers. Splitting a domain into subdomains and organizing a server for each of them is called delegating zone management rights to the appropriate domain name server, or simply delegating a zone.

When configuring a server, you can directly specify the addresses of zone servers in its configuration files. In this case, calls to the root server are not made, because the local server itself knows the addresses of remote zone servers, to which it delegated the rights to manage these zones.

There is another version of the server operation, when it does not query the root server for the address of the remote domain name server. This happens when, shortly before, the server has already resolved the task of obtaining an IP address from the same domain. If you need to get the IP address of the remote domain name server responsible for the domain, then it will simply be retrieved from the server's buffer (cache), because for a certain time specified in the zone description configuration (Time To Live - TTL), this address will be stored in the server's cache. And he got there as a result of the previous request.

In addition to a non-recursive name resolution procedure, a recursive name resolution procedure is also possible. It differs from the non-recursive procedure described above in that the remote server queries its own zone servers rather than providing their addresses to the local domain name server. Let's consider this case in more detail.

Figure 4 shows a non-recursive procedure for resolving an IP address from a domain name. The main load in this case falls on the local domain name server, which polls all other servers. In order to reduce the number of such exchanges, if volume permits random access memory, you can enable buffering (caching) of addresses. In this case, the number of exchanges with remote servers will be reduced.

In Figure 5, the remote domain server itself resolves a recursive request to obtain the IP address of its domain host by using a non-recursive query of its subdomain servers.

Fig 4. Non-recursive processing of a request by a local domain name server to obtain an IP address from a domain name.

Rice. 5. Recursive (for a local server) and non-recursive (for a remote server) procedures for address resolution by IP name.

Wherein local server immediately received from remote address host, not subdomain server addresses. To a remote server while serving recursive requests from the corresponding IP address must be allowed, the local server must contact the remote server with a recursive request.

The options presented here for how the domain name system works are not exhaustive. For more detailed information refer to RFC-1034 and RFC-1035.

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. Albitz P., Lee K.. DNS and BIND. - Per. from English. - St. Petersburg: Symbol-Plus, 2002. - 696 p.

1. http://www.microsoft.com/windows2000/en/server/help/sag_DNS_und_HowDnsWorks.htm?id=1945 - Microsoft Documentation for Windows 2000 Server. The section is devoted to the principles of the domain name system. Describes general principles building DNS and interaction between resolver and servers.
2. http://www.microsoft.com/windows2000/en/server/help/sag_DNS_ovr_ClientFeatures.htm?id=1942 - Microsoft Documentation for Windows 2000 Server. The section is devoted to the principles of operation of the resolver.
3. - Documentation for BIND 9. Help Guide system administrator. You should read the section on the lightweight resolver.
4. http://www.igc.ru/cgi-bin/man-cgi?traceroute - description of the traceroute command, since it was mentioned here.
5. http://www.menandmice.com/online_docs_and_faq/glossary/glossarytoc.htm - glossary of DNS terms.

The Internet is filled with billions of websites. Some of them function, develop, while others die off, are banned, closed. All life on the Internet is moving forward, as is real life on Earth, but every year the Internet enters our lives with confident steps and it is impossible to imagine existence without it.

As a rule, in order to have your site on the Internet, you need to register a domain (name) and purchase hosting (a place where all the files of your site will be stored).

I noticed such a problem that not all my acquaintances, friends, clients do not fully understand what domain and how they generally work together.

Today I want to write a whole article about what is domain name, domain zone and subdomains for the site, so that it would become clear to everyone.

What is a domain

Domain (domain name)- this is the address of the site on the Internet or, as they say, the name, designation. It can consist of letters (liter), numbers, dashes, words, as well as their combinations. Usually created from Latin letters from a before z, as well as numbers from 0 before 9 and a hyphen character, between words or letters.

Today it is possible to create Cyrillic domains, which may consist of letters from a before I, implemented specifically for Russia and the CIS countries.

Now let's bring not great example domain from our life. Look, every house in any of the countries has its own address, moreover it is unique. This address contains the name of the street - letters from a to z and the house number - numbers from 0 before 9 and possibly numbers and letters. The address is assigned to this house and it cannot be repeated within a certain city, town or country.

Something similar is happening on the web as well. There are billions domains, which have unique addresses (names), which are assigned to a specific domain zone.

What is a domain zone

Domain zone is a set of domain names that are included in a specific domain (zone). You can define the zone very easily. If you look at the site address, then what comes after the name and before the dot ‘.’ is the domain zone

For example:

loleknbolek is the domain name, and .ru is the (Russia) zone.

loleknbolek is the domain name, and .com.ua is the zone (Ukraine).

There are a lot of domain zones and they are divided into: common use and national.

Public domain zones are intended for use throughout the Internet space. These are such zones as: .com, .biz, .org, .net, .info and others.

National domain zones are intended for each of the states or geographical areas, as an example for Ukraine - .ua, Russia - .ru, USA - .us, Germany - .de. etc. These zones can be taken if you work only on the aisles of a certain country and at the same time outside the zone you are not interested in clients and visitors.

Domain levels

First level.

Domains from domain zones of common use and national ones. You can see prices, as well as registration rules at domain registrars.

Second level.

This is the name you are registering and must be unique. For our site, this is loleknbolek.

Third level.

These are usually subdomains, if it is necessary to create another site, service, forum on one large site, or make a multilingual site (in different languages).

Here are examples of third level domains:

forum.www.site

tools.www.site

What are subdomains

Subdomain is a third-level domain that can be created for free to solve the problems that I described above (forums, services, etc.). It will also be correct to use subdomains when there are several large sections on one site.

Create subdomain you can on your hosting, if you can’t deal with this issue, write to support, I can’t describe the creation process here, since it is different on all hostings.

Try to choose the most suitable area for yourself and make your sites more functional and for people.