DNS Lookup Tool

A DNS lookup queries the Domain Name System to resolve a domain name into its associated records. DNS maps human-readable names like 'google.com' to IP addresses, mail servers, and other network endpoints that computers use to route traffic.

An A record maps a domain to an IPv4 address (e.g. 93.184.216.34). An AAAA record maps a domain to an IPv6 address (e.g. 2606:2800:220:1:248:1893:25c8:1946). Most domains have A records; only dual-stack enabled domains also have AAAA records.

MX (Mail Exchange) records specify which mail servers receive email for a domain. Each MX record has a priority value — lower numbers have higher priority. When you send email to user@example.com, the sending server queries the MX records for example.com to find where to deliver the message.

TXT records store arbitrary text associated with a domain. Common uses include SPF (Sender Policy Framework) for email anti-spoofing, DKIM public keys, DMARC policies, domain ownership verification for Google Search Console and other services, and SSL certificate CAA records.

A CNAME (Canonical Name) record creates an alias from one domain to another. For example, www.example.com might CNAME to example.com. The DNS resolver follows the chain until it reaches an A or AAAA record. CNAMEs cannot coexist with other record types at the same name — you cannot CNAME the apex domain (example.com itself), only subdomains.

TTL (Time to Live) is how long resolvers and browsers cache a DNS record before re-querying. A TTL of 300 means the record is cached for 5 minutes. Lower TTLs allow faster propagation of changes but increase DNS query load. During a domain migration, you typically lower the TTL 24 hours in advance, then make the change, then restore the TTL.

DNS propagation takes time. When a record changes, the old value is cached by resolvers worldwide until its TTL expires. During the propagation window (usually minutes to 48 hours), different resolvers may return old or new values depending on when they last refreshed their cache. Geographic differences can also appear with anycast DNS and geo-steering configurations.

A SOA (Start of Authority) record identifies the primary DNS server for a zone and contains administrative information: the primary nameserver, the email of the responsible party, a serial number for zone updates, and refresh/retry/expire intervals used by secondary nameservers.