When we need to go to a certain website, we go to the browser and enter the domain, for example, example.ua. The system processes the request in milliseconds and opens the desired resource, so the process seems easy. However, everything is more complicated inside, and DNS plays an important role in this, a system that helps the browser quickly find the desired resource by its domain name. The owner of a web resource needs to understand the Domain Name System, because it helps to improve page loading speed, activate certain functions, and ensure the security of the site. In this article, VPS-UP specialists analyze the relevant topic in detail.
What is DNS and how it works
DNS (Domain Name System) is a distributed computer system that contains a database of public IP addresses and their associated hostnames. It converts domain names that people are familiar with (google.com, youtube.com, etc.) into corresponding IP addresses so that computers and networks can quickly find each other.
The process of computers and networks finding each other is similar to mobile communication: to call a person, we need their phone number. But today it is enough to save the number in Contacts, and if necessary, enter the name and call. When the system needs to find an IP address, it queries the DNS (a kind of telephone directory) to get the information it needs.
When we enter the address of a web resource in the address bar of a browser, we are instantly directed to it. And this is all thanks to certain stages of the DNS server’s work:
- Checking the local cache. When a computer sends a request, the local cache is checked first. If the system finds a relevant answer, the process ends at this stage.
- Request to the Internet provider’s DNS cache. If there is no information in the local cache or it is outdated, the computer sends a request to the DNS cache of the Internet provider (DNS Resolver), an intermediary server between the user’s device and the system.
- Accessing the root DNS servers. If the site data could not be found, the request is sent to the root servers – this is the first level of the hierarchy, which is responsible for the highest domain names (.com, .ua, .net, .org).
- Request to authoritative DNS servers. Next, the authoritative Domain Name System is contacted, which processes requests for the corresponding top-level domains.
- Request to the DNS server of your own domain. When the system receives information about the server’s IP address for the top-level zone, it will send a request to the server responsible for the top-level domain, i.e. site.com (for example, google.com).
- Obtaining an IP address. The DNS server of the top-level domain returns the IP address of the website, which is sent to the resolver.
- Returning the IP address to the computer. After receiving the IP address of the website from the DNS resolver, the computer stores it in its local cache for future use and establishes a connection to the web server at this IP address
Despite the complexity of the process described above, DNS works smoothly, so that domain names are quickly converted into IP addresses. This allows you to instantly connect and download the content of web pages with the content you need. In addition, you don’t need to enter a set of numbers every time, but just specify the domain of the site (for example, instead of 216.58.209.14, enter google.com).
Read also: What you need to know about server monitoring and backup – useful tips for customers
What are the types of domain DNS records
Within the Domain Name System, there are different types of records that are required to solve various tasks. Each type is responsible for a certain aspect of the domain name system and allows you to display different types of information, ensuring correct operation at any user requirement. For example, if mail is linked to a domain, then an MX record is needed: it will point to the server responsible for processing mail.
For better understanding, let’s analyze the main types of DNS domain records:
NS is a key element of the DNS system
NS (Name Server) is one of the main types of DNS records, a key element of the Domain Name System that points to authoritative servers for a particular domain. In addition to the main task, it is responsible for distributing the processing of requests (helps to improve performance), setting up subdomains, ensuring stability and reliability of the entire system.
A – is the most common record type
An A Record (Address Record) is a DNS record that directs a domain to a server’s IP address. When a person enters a domain in a browser, their request is sent to a DNS server using the A record, which returns the corresponding IPv4 address. This is already used to establish the connection and retrieve the page content.
Using several similar records for one domain allows you to expand the capabilities of your website. You can ensure the continuous operation of a web resource (if one server is unavailable, the signal is routed to another), distribute the load, and provide access from different networks.
AAAA is an improved version of the classic DNS record
AAAA (Quad A) is a type of DNS record used to map domain names to IPv6 addresses. It is rapidly gaining popularity due to the widespread global adoption of IPv6, an improved version of the Internet protocol that provides a huge address space.
CNAME – creating an alias for a domain
A CNAME is a DNS record that allows you to create alternative names and simplify the management of web resources. It is often specified when a subdomain is under development and you need to redirect users to the main site: blog.example.com to www.example.com.
Just keep in mind some CNAME restrictions: it cannot be placed in the root domain, and NS and MX records should never point to a CNAME. And it should not contain any other principal records with the same name (A, AAAA, MX, etc.) except for NSEC and RRSIG.
ALIAS – bypassing CNAME restrictions
ALIAS is a less common DNS record that is used to set up alternative aliases that point to the original canonical domain name. It is an unofficial DNS record, but some hosting providers support it.
ALIAS, unlike CNAME, has fewer restrictions. CNAME only allows you to specify a subdomain (another domain or subdomain within your site). Whereas ALIAS allows you to specify the root domain, which is very important because some services require it.
TXT – convenient transfer of text information
TXT (Text) is a common type of DNS record that contains human-readable information. It is often used in conjunction with other DNS records to provide additional information. There can be several TXTs on one domain, so it is often used to confirm ownership (Google Search Console, Google Analytics, various affiliate programs) and add anti-spam filters.
MX – stable email processing
An MX (Mail Exchange) is a DNS record that points to the servers responsible for processing emails for a particular domain. It is used to direct emails sent to addresses located on a particular domain to the appropriate mail servers for processing and delivery.
SRV – opening the server location
An SRV is a DNS record that indicates the presence of a specific service on a network. It makes the location of the server visible through the host name and port number, allowing you to attach multiple hardware to the same domain and specify a priority for each. SRV is used to connect a specific service, such as IP telephony.
Conclusion
DNS is an integral part of the modern digital world that allows you to convert human-readable domain names into IP addresses that are used for routing and connecting to web servers. This technology is very important for website owners and web optimizers, as it allows them to add necessary functions to their websites, increase page loading speed, and protect their websites from DNS attacks.
When you register a hosting and connect a domain, certain DNS records (usually A, AAAA, NS, MX, CNAME) are automatically added to the database of the respective provider. Then you can manage the data yourself by adding your own DNS records, for example, to confirm ownership or connect the necessary services. Only when adding a record
