DNS Resolution
PCLocal HostDNSISP ResolverSVRgoogle.com
Query Status
Idle
Record Type
A (IPv4)
Resolved IP
—

A records map a domain name to an IPv4 address. Your domain points to the server at this address. If you recently changed hosting providers, compare this address with the one your new provider supplied.

What Is DNS?

DNS (Domain Name System) is often called the phonebook of the Internet. It translates human-readable domain names like google.com into IP addresses that computers use to communicate. Without DNS, you would need to remember numeric IP addresses for every website you visit.

Every time you type a URL into your browser, a DNS query runs behind the scenes to find the server that hosts that website. The system is distributed across millions of servers worldwide, forming a hierarchical network that can resolve billions of queries every day.

DNS is not limited to websites. It underpins email delivery, API calls, VPN connections, and virtually every service that communicates over the Internet. Understanding how DNS works is essential for diagnosing connectivity problems and managing domains.

DNS Record Types Explained

A Record
Maps a domain to an IPv4 address. The most common DNS record type. When you visit a website, an A record is typically what connects the domain name to the server's IP address.
AAAA Record
Maps a domain to an IPv6 address. Works the same as A records but for the newer protocol. IPv6 addresses are longer and allow for a vastly larger address space than IPv4.
MX Record
Specifies which mail servers accept email for the domain. Includes a priority number — lower priority means higher preference. Multiple MX records provide fallback mail servers if the primary is unavailable.
TXT Record
Holds arbitrary text. Used for email authentication (SPF, DKIM, DMARC), domain verification, and other purposes. Many third-party services require you to add a TXT record to prove domain ownership.
NS Record
Lists the authoritative name servers for the domain. These servers are the definitive source for the domain's DNS records. Changing NS records effectively delegates control of your DNS to a different provider.
CNAME Record
Creates an alias from one name to another. For example, www.example.com might be a CNAME pointing to example.com. The browser follows the alias and resolves the target name to get the final IP address.
SOA Record
Contains administrative metadata about the DNS zone, including the primary name server, serial number, and refresh timers. Every DNS zone has exactly one SOA record, and it governs how secondary servers synchronize with the primary.

How DNS Resolution Works

  1. Local cache check — Your device checks its local DNS cache for a previously resolved answer. If a valid (non-expired) entry exists, it is returned instantly.
  2. Recursive resolver query — If not cached, your device queries your ISP's recursive resolver (or a public resolver like 8.8.8.8). This server does the heavy lifting of tracking down the answer.
  3. Root name servers — The resolver queries one of the 13 root name server clusters to find which TLD (Top-Level Domain) server is responsible for the domain's extension (e.g., .com, .org).
  4. TLD server referral — The TLD server directs the resolver to the domain's authoritative name server, which is registered when the domain is set up.
  5. Authoritative response — The authoritative name server returns the requested DNS record (A, MX, etc.) to the resolver.
  6. Caching and response — The resolver caches the result for the duration specified by the record's TTL (Time To Live) and returns it to your device.

Troubleshooting DNS Issues

  • Domain not resolving — Check that NS records point to the correct DNS provider. If you recently transferred your domain or changed name servers, ensure the update has propagated.
  • Email not working — Verify that MX records match your email provider's recommended configuration. Incorrect priorities or missing records are common causes of email delivery failures.
  • Recent changes not visible — DNS changes can take up to 48 hours to propagate globally, depending on the TTL of the old records. You can flush your local DNS cache or query alternative servers to check progress.
  • SSL certificate errors — Ensure A/AAAA records point to the server that holds the correct SSL certificate. A mismatch between the domain and the server's certificate will trigger browser security warnings.

Learn More

Read our in-depth guide to understand the concepts behind this tool:

  • What Is DNS? — How the Domain Name System works, record types, caching, security, and troubleshooting.

Frequently Asked Questions

How long do DNS changes take to propagate?

DNS propagation depends on the TTL (Time To Live) value of the records. Most changes take 1–24 hours, but some resolvers may cache records for up to 48 hours. You can check propagation by querying different DNS servers.

What is DNS propagation?

DNS propagation is the time it takes for updated DNS records to spread across all DNS servers worldwide. During this period, some users may see old records while others see the new ones.

What DNS server should I use?

Common public DNS servers include Google (8.8.8.8), Cloudflare (1.1.1.1), and OpenDNS (208.67.222.222). They are generally fast and reliable. Your ISP also provides DNS servers automatically.

Why do I get different DNS results from different locations?

Large services use GeoDNS to return different IP addresses based on your location, directing you to the nearest server. CDNs like Cloudflare and AWS CloudFront use this extensively.