What is a DNS Checker?
DNS records are the address book of the internet: A/AAAA point a domain at servers, MX routes its email, TXT carries verifications and SPF, and NS says who is authoritative.
This checker queries all record types in parallel and lays them out in one view: the first stop when a site is unreachable, email bounces, or a verification will not go through.
Reading results like an engineer: no A/AAAA record means the domain simply does not point anywhere. MX missing means email to that domain bounces. NS records answer 'who controls this zone': the first thing to check when changes made at one provider mysteriously do not appear. TXT is where verification codes and SPF live.
Why a correct answer here can still differ from what a visitor sees
This lookup asks a public resolver and reports what it returns right now. A visitor somewhere else can genuinely get a different answer, for three ordinary reasons rather than anything being wrong.
Caching is the usual one. Every resolver between a visitor and the authoritative server is allowed to hold the previous answer until its TTL runs out, so a record you changed an hour ago can still be the old value for somebody whose resolver cached it for a day. Geographic routing is the second: a domain behind a CDN or a GeoDNS provider deliberately answers with different addresses depending on where the question comes from, so two correct lookups disagree by design. The third is split-horizon DNS, where a company network answers internal queries from a private zone, which is why a site can resolve at the office and nowhere else.
The practical consequence: when a change looks missing, compare against the authoritative nameservers rather than against one resolver, and check the TTL that was in force before the change, because that is the window you are waiting out.
Frequently asked questions
What is TTL and why does it matter?
Time-to-live: how long resolvers cache an answer. A 3600s TTL means changes can take an hour to appear everywhere. Lower TTL before planned changes, raise it after.
Why do results differ from my own machine's?
Your OS and router cache DNS answers too. This checker queries live resolvers, so it shows current truth while your laptop may hold yesterday's answer.
Which record types does it check?
A (IPv4), AAAA (IPv6), CNAME, MX (mail), NS (nameservers) and TXT: the set involved in virtually every DNS problem.
My change doesn’t show yet: is something wrong?
Probably just propagation: resolvers cache answers for the record’s TTL. Use the DNS Propagation Checker to watch the change spread.
What does a CNAME mean?
The domain is an alias for another name: the browser follows the chain until it reaches an A/AAAA record.
Why do I see several A records?
Multiple addresses are normal: they spread load and add redundancy across servers.