DNS Record Checker

DNS (Domain Name System) records are instructions stored on authoritative nameservers that map human-readable domain names to the technical data browsers and services need to connect. Think of DNS as the internet's phone book — you look up a name (example.com) and get back a number (93.184.216.34). The most common record types are: A records which map a domain to an IPv4 address; AAAA records which map to IPv6 addresses; CNAME records which create aliases pointing one domain to another; MX records which specify the mail servers that handle email for the domain; TXT records which store arbitrary text data (commonly used for SPF DKIM and domain verification); NS records which delegate a domain to specific nameservers; and SOA records which contain administrative information about the DNS zone. Every domain needs at least an A or AAAA record to be reachable on the web and MX records to receive email. TXT records have become increasingly important for email authentication (SPF DKIM DMARC) and proving domain ownership to services like Google Microsoft and various SaaS platforms. DNS records have a TTL (Time to Live) value that controls how long resolvers cache the record. Lower TTLs mean changes propagate faster but generate more DNS traffic. Most sites use TTLs between 300 seconds (5 minutes) and 86400 seconds (24 hours).

DNS propagation is the time it takes for DNS record changes to be recognized across the internet. When you update a DNS record the change doesn't take effect everywhere simultaneously. Instead it spreads gradually as cached copies of the old record expire at DNS resolvers worldwide. The primary factor controlling propagation speed is TTL (Time to Live). If your previous record had a TTL of 3600 seconds (1 hour) resolvers that cached the old record will continue serving it for up to an hour before checking for updates. This is why experienced administrators lower TTLs well before making critical DNS changes — set the TTL to 300 seconds a day or two in advance make the change then raise it back. In practice most DNS changes propagate within 1-4 hours for records with standard TTLs. However some ISP resolvers and corporate networks ignore TTLs and cache aggressively which can extend propagation to 24-48 hours in rare cases. To speed things up: lower your TTL before making changes use a DNS provider with a fast global network and clear your local DNS cache (ipconfig /flushdns on Windows sudo dscacheutil -flushcache on Mac). To watch a change spread in real time use our dedicated DNS Propagation Checker which queries the record across multiple global resolvers at once and shows you exactly which have caught up.

A DNS checker queries authoritative nameservers for your domain's A AAAA MX TXT CNAME NS and SOA records then compares the answers against what you expect. It surfaces propagation delays record mismatches stale caches and misconfigured subdomains before they break production.

Propagation is measured by querying DNS from multiple geographic resolvers at the same time. If every resolver returns the same answer the record is fully propagated. If regions disagree you're mid-propagation — typical duration is 5 minutes to 48 hours bounded by the record's TTL. Lower TTL before you plan a change and propagation tightens to minutes.

Three likely causes: local OS cache (flush with sudo dscacheutil -flushcache on macOS or ipconfig /flushdns on Windows); ISP resolver cache (honors TTL but sometimes slowly); and the record's own TTL. If TTL is 86400 (1 day) that's your worst-case wait. Drop TTL to 300 before any planned change deploy the change then raise TTL back once verified.

Both map a hostname to an IP. A records point to IPv4 (32-bit e.g. 93.184.216.34); AAAA records point to IPv6 (128-bit e.g. 2606:2800:220:1:248:1893:25c8:1946). A domain can publish both. If you only publish AAAA clients without IPv6 connectivity — including many corporate networks — cannot reach you.

For stable production records: 3600 (1 hour) to 86400 (1 day). For records you plan to change soon: 300 (5 minutes). Low TTL increases query volume to your authoritative nameservers — this is almost always fine unless you run them yourself. Mismatched TTLs between A/AAAA/CNAME for the same host usually signal a config drift worth fixing.