DNS Tools
DNS problems are usually one of three things: the record is wrong, the record is right but not yet visible, or you are looking at the wrong zone entirely. These tools separate those cases. Start with a lookup to see what authoritative servers publish, then use the propagation checker to see what the rest of the world currently has cached.
Diagnostic order
All dns tools
Delegation, glue, lame nameservers, SOA serials, reachability, DNSSEC chain
All DNS records for a domain in one query
IPv4 addresses a hostname resolves to
IPv6 addresses for a hostname
Alias target of a hostname
Authoritative nameservers for a domain
All TXT records — SPF, verification, and more
Zone serial, refresh, and primary nameserver
Which certificate authorities may issue for a domain
Service records for SIP, XMPP, and more
Is a zone signed, and does it validate?
Same query against Google, Cloudflare, Quad9, OpenDNS side by side
Guides for dns tools
What actually controls propagation time — TTLs, resolver caches, and registrar delays.
A checklist for records that refuse to update: caching, wrong zone, and stale nameservers.
The TTL-lowering timeline that makes DNS cutovers near-instant.
Telling a broken zone apart from a name that simply does not exist.
When to point with an alias and when to use a direct IP.
What this Chrome error means and how to fix it on your site or your device.