DNS Diagnostics
Query DNS records for any domain from public resolvers, bypassing your local cache.
Why query from public resolvers
Your operating system caches DNS answers, and your ISP resolver may keep serving stale records during propagation. Asking public resolvers (Cloudflare, Google) directly gives you the authoritative-enough view of what the world sees right now.
Reading each record type
A / AAAA map a hostname to IPv4 / IPv6 addresses; CNAME is an alias; MX lists mail servers in priority order; TXT carries SPF / DKIM / verification strings; NS delegates the zone; CAA restricts which CAs may issue certificates.
Diagnosing propagation
Changed a record but still see the old value? Compare TTLs and query different resolvers here — if Cloudflare shows the new value but Google still shows the old, propagation is simply in flight.
Need the in-depth Chinese version? Read the full guide.
Related articles
DNS Resolvers and Encrypted DNS: What 8.8.8.8 and 1.1.1.1 Actually Do
What actually changes when you switch DNS to 8.8.8.8? How recursive resolvers work, the dimensions for comparing public DNS, and what DoH/DoT encrypted DNS can and can't protect — covered in full, in one piece.
DNS Leaks Explained: How They Happen, How to Detect Them, and How to Prevent Them
You're on a proxy — why can others still see which sites you visit? DNS leaks are the most common failure point for proxy users; the DNS resolution flow, where leaks occur, how to self-test, and how to plug them.
How CDNs Work: Why the IP You Look Up Isn't the Origin Server
You look up a website and the IP shows Singapore, Virginia, or Frankfurt — because what you found is usually a CDN node, not the origin; how CDN scheduling works, X-Cache headers, origin pulls, and what it all means for IP geolocation and speed tests.
What Is an IP Address? IPv4, IPv6, Public and Private, Explained in One Pass
A plain-language explanation of what IP addresses do, how IPv4 and IPv6 differ, how to tell public from private IPs, and why the IP you see isn't the one others see.
More in the blog index
Frequently asked questions
Why does the result differ from nslookup on my machine?
Your local resolver caches answers for the TTL duration, and some ISPs override answers. This tool queries public resolvers directly, so it shows what independent resolvers see.
What is a CAA record for?
CAA declares which certificate authorities are allowed to issue certificates for the domain. It is a hardening measure; absence of CAA does not prevent issuing certificates.
Can I check email deliverability here?
Partly — MX, SPF (TXT) and DKIM selectors are visible. For deep diagnostics use a dedicated mail-testing service.