WHOISDNS Tools
Query and troubleshoot DNS records directly.
What are DNS tools?
DNS tools show you what the Domain Name System is telling the world about a domain. DNS decides where a website loads from, which servers receive its email and which text records prove ownership to other services. When a site disappears after a move or email stops arriving, the answer is almost always in these records, and DNS tools let you read them directly instead of guessing.
The five DNS tools below each look at the same system from a different angle, from a single record to a full health check.
What each DNS tool does
DNS Lookup reads A, AAAA, CNAME, MX, NS, TXT and SOA records for a domain or subdomain. Choose one record type or show all seven together, with quick diagnostics for SPF, DMARC, mail servers and nameservers.
NS Lookup lists the nameservers in charge of a domain's zone and resolves each one to its IPv4 address, which reveals the DNS provider and shows whether there is redundancy.
MX Lookup lists the mail servers for a domain in priority order, resolves each to its IPv4 and IPv6 addresses, and warns when a server name does not resolve.
Domain DNS Health Checker runs six equally weighted checks, covering nameservers, address records, MX, SPF, DMARC and SOA, and turns them into a percentage score.
DNS Propagation Checker asks six public resolvers, from Cloudflare, Google, Quad9 and OpenDNS, for one record and compares each answer with the domain's own authoritative nameserver.
When to use which DNS tool
Checking a record you just changed
Start with DNS Lookup to confirm the new value is published. If some people still see the old one, the DNS Propagation Checker shows which public resolvers are still serving a cached copy.
Moving to a new DNS provider
Use NS Lookup to see which nameservers the internet currently follows. Once the switch shows up, run DNS Lookup on the new zone to make sure every record was copied across.
Setting up or fixing email
MX Lookup confirms where incoming mail is delivered. The Domain DNS Health Checker then shows at a glance whether SPF and DMARC exist alongside the mail servers.
Problems these DNS tools help solve
- A website still loads from the old host after a migration.
- Email bounces or arrives at an old provider.
- A verification TXT record is not being found by another service.
- A domain has only one nameserver, so a single outage takes it offline.
- Some visitors see a change while others still see the old version.
- A mail server name in an MX record does not resolve to any address.
How DNS caching affects results
Every DNS answer carries a TTL, the number of seconds resolvers may keep it before asking again. That is why a correct change can take minutes or hours to reach everyone. Lowering the TTL a day before a planned change makes the switch much quicker. DNS Lookup asks through our server's resolver, while the DNS Propagation Checker asks six public resolvers directly and keeps its own results for only 30 seconds.
Related categories
DNS points a name at servers, so the next step is often to check those servers. IP Tools show who runs an address, Website Tools check that the site responds, and Email Tools go deeper on SPF, DKIM and DMARC. For registration details, see Domain Tools.
Frequently asked questions
What do DNS tools check?
They read the records a domain publishes in the Domain Name System: addresses for the website, mail servers, nameservers, text records such as SPF and verification codes, and the zone's SOA record. Some also compare answers between public resolvers or score the overall setup, so you can see problems before visitors do.
Why do different DNS tools show different results?
Resolvers cache answers for the length of each record's TTL, so two tools asking different resolvers can briefly see different values after a change. Our DNS Propagation Checker compares six public resolvers against the domain's own nameserver, which shows whether a difference is just caching or a real mistake.
How long does a DNS change take to work?
Usually as long as the old record's TTL, which is often an hour or less. Nameserver changes can take up to 48 hours because NS records tend to have long TTLs. Lowering a record's TTL a day before you change it helps the new value spread faster.
Which DNS tool should I use first?
Start with DNS Lookup and choose All Records. It shows the seven most common record types on one page with short diagnostics. Move to NS Lookup, MX Lookup or the DNS Propagation Checker when you need more detail about nameservers, mail servers or caching.
Can I check subdomains with these DNS tools?
Yes. Enter the full name, such as shop.example.com, in DNS Lookup or the DNS Propagation Checker. Records belong to one exact name, so a subdomain can point somewhere different from the main domain. NS Lookup usually returns nothing for a subdomain unless it has been delegated to another provider.
Does the DNS Health Checker test DKIM?
No. DKIM keys are published under a selector name chosen by each email provider, and DNS has no way to list them. The health checker covers nameservers, address records, MX, SPF, DMARC and SOA. Use the DKIM Checker in Email Tools with your selector to test DKIM.
Do I need to know DNS well to use these tools?
No. Each tool explains its results in plain language, and the diagnostics mark items as passing, worth checking or failing. Warnings can be deliberate choices, for example no mail servers on a domain that never receives email, so read the explanation before changing anything.