A DNS lookup is a query you make to find information about a domain name's DNS records. When you enter a domain like example.com into a DNS lookup tool, it queries DNS servers to retrieve records that tell computers where to send email (MX records), which IP address to load the site from (A records), and other essential configuration data. DNS lookups are how the internet translates easy-to-remember domain names into numeric IP addresses that computers use to communicate.

There are many DNS record types, but the most common are: A records map a domain to an IPv4 address; AAAA records do the same for IPv6 addresses; CNAME records create aliases pointing one domain to another; MX records specify email servers for the domain; TXT records are used for domain verification and email authentication (SPF, DKIM, DMARC); NS records show which nameservers handle the domain; SOA records contain administrative information; CAA records specify which certificate authorities can issue SSL certificates. Each serves a specific purpose in how your domain works online.

An A record maps a domain directly to an IP address, like pointing example.com to 192.168.1.1. A CNAME record maps one domain to another domain instead, like pointing blog.example.com to example.com. Use A records when pointing to an IP address that won't change. Use CNAMEs when pointing to another domain that might change—CNAMEs are more flexible because you only need to update the target domain's records, not every CNAME pointing to it. You cannot use a CNAME for the root domain (example.com) in most cases.

DNS propagation typically takes between a few minutes to 24 hours, though in rare cases it can take up to 48 hours. When you change DNS records, your registrar updates the root nameservers, and those changes must spread to all DNS servers worldwide. Most changes are visible within a few hours. The TTL (Time To Live) value on your records affects propagation speed—lower TTLs mean faster propagation but more load on DNS servers. After 48 hours, if changes haven't propagated, there's likely a configuration error.

Use a DNS lookup tool like this one to check your records from different geographic locations. Since different DNS servers around the world update at different times, you might see old and new results depending on which server responds to your query. Some tools show which DNS server provided the response, helping you identify propagation status. If you see your new values consistently from multiple sources, propagation is complete. Remember that local DNS caches on your computer or network might still show old values even after global propagation.

An MX (Mail Exchange) record tells email servers where to deliver email sent to your domain. Without MX records, emails sent to user@example.com would bounce because mail servers wouldn't know where to send them. MX records have a priority value (like 10, 20) where lower numbers indicate higher priority. If you have multiple MX records, mail servers try the lowest number first and fall back to higher priorities if the primary server is unavailable. Common email providers like Google Workspace and Microsoft 365 provide specific MX records you need to configure.

TXT records originally allowed administrators to add arbitrary text notes to a domain, but they've become essential for email security and domain verification. SPF (Sender Policy Framework) TXT records specify which mail servers are authorized to send email from your domain—receiving servers check this to prevent email spoofing. DKIM and DMARC records are also TXT records that authenticate email. Domain verification for services like Google Search Console uses TXT records to prove you own the domain. Some services use TXT records for other verification purposes too.

Use this DNS lookup tool and query for NS records. The results will show the nameservers responsible for your domain, typically listed as something like ns1.example.com and ns2.example.com. Nameservers are defined at your domain registrar, where you purchased the domain. If you're using a hosting provider, they usually provide nameservers you'll configure at your registrar. Checking NS records helps verify your domain is pointing to the correct nameservers after a migration or when troubleshooting DNS issues.