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09. 08. 2026 When you enter a website address into your browser (e.g., google.com), computers and routers do not natively understand that text. They communicate using numerical IP addresses. The Domain Name System (DNS) is a fundamental internet service that translates human-readable domain names into machine-readable IP addresses.
How a DNS Lookup Works
Finding the correct IP address occurs within milliseconds across a hierarchy of specialized DNS servers.
| DNS Server | System Role | Description |
|---|---|---|
| DNS Resolver | First Point of Contact | Usually operated by your ISP, initiates and manages the lookup resolution. |
| Root Server | Root Nameserver | Directs the query based on the top-level domain (.com, .org, .si). |
| TLD Server | Top-Level Domain Server | Holds references to authoritative servers for specific domain extensions. |
| Authoritative Server | Final Authority | The final server holding the actual IP record for the target domain. |
Common Types of DNS Records
Domain zones contain specific record types to route web traffic and auxiliary services appropriately.
- A Record (Address): Maps a domain name directly to an IPv4 address.
- AAAA Record: Maps a domain name directly to an IPv6 address.
- CNAME (Canonical Name): Aliases one domain or subdomain to another hostname.
- MX Record (Mail Exchange): Specifies the mail server responsible for receiving emails for the domain.
- TXT Record: Stores text data (commonly used for domain ownership verification and email security SPF/DKIM).
Importance of DNS Caching
To avoid querying root servers repeatedly, your operating system, router, and ISP resolver cache DNS records for a duration specified by the TTL (Time To Live) setting. When updating IP addresses in DNS settings, changes propagate worldwide as cached TTL records expire.
Why DNS Matters for Webmasters
Properly configured DNS records ensure continuous site availability, protect outgoing email from being flagged as spam, and enable seamless traffic migration between host servers.