DNS – What Is It & What Is Its Use?

Displaying the contents of a website on a computer’s screen is possible thanks to an appropriate network connection. The client, or a web browser, is on one side, and a server with the website’s resources is on another. In order for the connection to be successful, protocols like HTTP or HTTPS and a DNS are used. Learn what is a DNS, what is its operation scheme, what functions and basic domain types it supports.

What Is a DNS Protocol?

A system, a primary task of which is to convert domain names written as words into IP addresses – that is what DNS is in a nutshell. The protocol, the full name of which stands for Domain Name System, enables conversion of a domain name into an IP address, so that a browser on a computer will later be able to load the page, using the HTTP or HTTPS protocol.

By way of tradition, the WWW domain names are shown in letter form, e.g. http://mydomain.com. Such a string is comprehensible and easy to memorize for humans, however, another system – numerical (IP address) – is “natural” for computers. To make it possible to show the page upon entering the WWW address in a web browser, it’s necessary to translate the letter notation into an IP address – and that’s what DNS servers do. In some sense this system can be compared to a list of contacts in your phone: just like specific people have specific numbers assigned to them in a phone book, websites have IP addresses assigned as well.

DNS Server Function

Connecting to a host happens very fast, and with modern infrastructure WWW pages show up on our screens in a split second after entering the address in the browser’s bar. However, not everyone realizes that it’s a multi-threaded process, so it’s important to learn not only what a domain name system is, but also its principle of operation. It can be presented in 3 subsequent steps.

1. An Internet user picks the page’s address, like mydomain.com, by typing it into the browser’s window.
2. The system connects to a local or a remote DNS server, requesting translation of the page’s name into the IP address.
3. In return, the DNS Server outputs information to the computer in a form of an IP address that makes the connection, so that the website can be displayed on a monitor.

Structure & Hierarchy of the Domain Name System

The naming system of Internet domains has a two-level structure: it involves top-level and second-level domains. Top level domains (TLD) include:

• national domains, ending with a dot and a two-letter country extension following it, e.g., .pl, .uk, .de, .fr, .es, etc.;
• functional addresses, ending with the following extensions: .com, .edu, .gov, .org, .info or .biz.

Besides that the Domain Name System also forwards second-level addresses, or regional domains. In case of Poland, those are, e.g. slask.pl, warszawa.pl, pomorskie.pl, and others.

DNS Server Classification

Getting a question of what a domain name system is itself answered, and learning about its hierarchical structure does not present one with a full picture of the protocol operation. Also, the distinction of top and authoritative domain levels is worth considering.

The root, i.e. the top domain server, is a category including DNSs located all over the world. When connecting to the Internet, the intermediary server “queries” the top one, in order to subsequently respond to the browser, which displays the website’s contents on a device screen.

In turn, authoritative devices are none other than local machines, storing the current data on computers working under a given domain. With a setup with more than one DNS server you will have a Master Server and a Slave Server. The first one stores master data for the domain and its configuration. This data is transmitted to Slave-type devices, which can be used as alternative or backup in relation to the Root.

What Does the DNS Server Response Time Depend on?

The time needed to locate the right IP address of a given domain greatly impacts the page loading speed in a browser. The factors which can extend this time are slow Internet connections, server load or implemented network management solutions.

It’s important to keep in mind that the speed of loading a website also depends on its architecture. Many WWW platforms contain media, links to external services (e.g. social media plugins) or advertisement assets among other things, and this significantly impacts the time needed to load the page. External factors, such as the speed of your connection or the performance of the hosting service, are of no small importance as well.

Types of DNS Queries

Just like domains, the domain name system queries are subject to proper classification. We distinguish between two basic types.

• Recursive queries – force the lookup of data about a specific domain, or send an error message. No response from the queried device results in forwarding the query to other DNSs.
• Iterative queries – when no IP address can be obtained, they do not force the connection with other locations.

The Domain Name System – The Cornerstone of Internet Functioning

In spite of the fact that not many people think about it, the Domain Name System is one of the foundations of how the Internet works. The Domain Name System affects not only WWW pages, but a range of other web services, such as e-mail or web applications as well. That’s why it’s worth being aware of not only what the DNS server is and what are its uses, but also how it works. DNS protection is a crucial piece of network system security, and it should be implemented whenever one seriously considers safety. You can benefit from the experience and expertise of Grandmetric Sp. z o.o. Experts – go for IT security system integration and tailoring.