When a user enters a website address in the browser, for example, example.ua, the system finds the required server and opens the web resource in a fraction of a second. This process is managed by DNS (Domain Name System) — a system of domain names that converts human-readable domains into IP addresses of servers.
DNS plays an important role in the operation of websites, connection speed, email configuration, and the security of web resources. Understanding how DNS works helps better manage the domain, correctly configure web services, and avoid issues with website availability.
What is DNS and how does the domain name system work
DNS (Domain Name System) — is a system of domain names that converts human-readable website addresses into IP addresses of servers. Thanks to DNS, users do not need to remember sets of numbers like 216.58.209.14 — it is enough to enter a domain in the browser, for example, google.com.
The principle of how DNS works can be compared to a phone book or a contact list on a smartphone. To call a person, we do not memorize the phone number but choose the contact's name. DNS works similarly: the system finds the IP address corresponding to the domain name and helps the browser connect to the required server.
When a user enters a website address in the browser, DNS goes through several stages of processing the request:
- checking the local cache — the system first checks if the IP address of the website is stored on the user's device;
- querying the provider's DNS resolver — if the data is not available or is outdated, the request is sent to the ISP's DNS server;
- querying the root DNS servers — the system determines which server is responsible for the required domain zone (.com, .ua, .net, etc.);
- querying the authoritative DNS server — the IP address of the server to which the domain is linked is obtained;
- returning the IP address to the user — the browser receives the required address and establishes a connection to the website.
All these processes occur in a fraction of a second, so accessing a website seems instantaneous. DNS ensures the quick opening of web resources, correct traffic routing, and stable operation of websites and online services.
Also read: What you need to know about server monitoring and backup – useful tips for clients
What types of DNS records are there for a domain
DNS uses various types of records, each responsible for a specific function in the operation of a domain, website, or email services. It is the DNS records that determine which server the domain points to, how email works, which services are connected to the website, and how individual user requests are processed.
For example, if email is connected to the domain, MX records are used to specify the mail servers for receiving emails. A or AAAA records are used to link the domain to the server, and CNAME is used to create aliases.
NS — name servers
NS (Name Server) — is one of the key types of DNS records that specifies the authoritative DNS servers for the domain. They store the DNS zone and are responsible for processing DNS requests for a specific domain.
A — linking a domain to an IPv4 address
An A record (Address Record) is used to link a domain or subdomain to an IPv4 address of a server. When a user enters a website address in the browser, the DNS system uses the A record to find the server's IP address and establish a connection to the web resource.
Multiple A records can be used for a single domain — for example, for load balancing or service redundancy.
AAAA — DNS record for IPv6
An AAAA record works similarly to an A record, but is used for IPv6 addresses. With the gradual global implementation of IPv6, such records are becoming increasingly common.
CNAME — creating aliases
CNAME (Canonical Name) allows you to create an alias for a domain or subdomain. For example, it can be used to point blog.example.com to www.example.com.
CNAME is most often used for subdomains. According to DNS standards, it is not recommended to use it for the root domain and to combine it with other primary DNS records for the same name.
ALIAS — an alternative to CNAME for the root domain
ALIAS — a less common type of DNS record that is not supported by all DNS providers. It is used as an alternative to CNAME in cases where it is necessary to point the root domain to another domain or service.
TXT — text DNS records
TXT records are used to transmit text information via DNS. They are most often used to verify domain ownership, configure SPF, DKIM, and DMARC, as well as for the operation of various external services.
MX — email operation
MX (Mail Exchange) defines the mail servers responsible for receiving emails for the domain. These records ensure the correct delivery of emails to addresses like info@example.com.
SRV — DNS records for services
SRV records are used to define the location of individual network services. They contain information about the server, port, and connection priority and are often used for IP telephony, messengers, and corporate services.
DNS — is one of the fundamental technologies of the modern internet, which provides a connection between domain names and IP addresses of servers. Thanks to DNS, users can open websites using understandable addresses instead of using sets of numbers. Proper DNS configuration affects the stability of the website's operation, connection speed, email functionality, and the security of the web resource.
After registering a domain and connecting hosting, the main DNS records are usually created automatically. Subsequently, the website owner can manage the DNS zone independently: adding new records, connecting external services, configuring email, or verifying domain ownership.
When changing DNS records, it is important to carefully check the parameters and values of the records, as errors in the settings can affect the availability of the website or the operation of individual services.