DNS Lookup

What Is DNS and How Does It Work?

The Domain Name System (DNS) is often referred to as the phonebook of the internet. It translates human-readable domain names like example.com into machine-readable IP addresses such as 93.184.216.34. Without DNS, users would need to remember numeric IP addresses to visit every website. When you type a URL into your browser, a DNS query is sent through a chain of servers -- starting with a recursive resolver, then root name servers, TLD (top-level domain) servers, and finally authoritative name servers -- until the correct IP address is found and returned. This entire process, known as DNS resolution, typically completes in milliseconds.

DNS Record Types Explained

DNS records are stored on authoritative name servers and contain various types of information about a domain. Each record type serves a specific purpose in the domain name system:

• A Record -- Maps a domain name to an IPv4 address (e.g., 93.184.216.34). This is the most fundamental DNS record type and is used every time a browser connects to a website.
• AAAA Record -- Maps a domain name to an IPv6 address (e.g., 2606:2800:220:1:248:1893:25c8:1946). As IPv4 address space becomes exhausted, AAAA records are increasingly important for modern internet infrastructure.
• CNAME Record -- Creates an alias from one domain name to another. For example, www.example.com might be a CNAME pointing to example.com. CNAME records are commonly used for subdomains and CDN configurations.
• MX Record -- Specifies the mail servers responsible for receiving email for a domain, along with priority values that determine the order in which mail servers are tried.
• NS Record -- Identifies the authoritative name servers for a domain. NS records delegate a DNS zone to a specific set of name servers.
• TXT Record -- Holds arbitrary text data associated with a domain. TXT records are widely used for email authentication (SPF, DKIM, DMARC), domain verification, and security policies.
• SOA Record -- The Start of Authority record contains administrative information about a DNS zone, including the primary name server, the responsible party's email, zone serial number, and refresh/retry timing parameters.

DNS Propagation and TTL

When DNS records are updated, the changes do not take effect instantly across the entire internet. DNS resolvers cache query results for a duration specified by the record's Time to Live (TTL) value. DNS propagation is the time it takes for updated records to spread across all DNS servers worldwide, which can range from a few minutes to 48 hours depending on TTL settings and caching behavior. Lowering the TTL before making planned changes can help speed up propagation. Our free DNS lookup tool lets you query the current DNS records for any domain in real time, helping you verify configurations, troubleshoot email delivery issues, and confirm that DNS changes have propagated correctly.