A DNS lookup shows the records that tell the internet where a domain’s website, email and other services live. The tool above checks eight record types at once, A, AAAA, CNAME, MX, NS, TXT, CAA and SOA, and explains each record in a sentence, so you can see what a domain is set up to do without decoding raw output. It works for root domains like example.com and for host names like www.example.com or shop.example.com.

What DNS Does

DNS, the Domain Name System, is the internet’s address book. People and programs use names like example.com, but computers connect using numeric IP addresses. When you visit a website or send an email, your device asks a DNS resolver to look up the domain’s records, and the answers tell it which server to contact.

Each domain’s records are stored on its name servers, usually run by the registrar, a DNS provider such as Cloudflare, or a hosting company. Resolvers around the world fetch those records and keep copies for a while, which is why changes don’t appear everywhere at the same moment.

The Record Types We Check

Each record type does one job. These eight cover almost everything a typical domain needs:

• A: the IPv4 address of the server for this name, the record that makes a website load
• AAAA: the IPv6 address of the server, for networks that use the newer address format
• CNAME: an alias that points one name at another, common for www and for services like Shopify or GitHub Pages
• MX: the mail servers that receive email for the domain, with a priority number for each
• NS: the name servers that hold the domain’s DNS records and answer questions about them
• TXT: text records used for email security, such as SPF and DMARC, and for proving ownership to services like Google and Microsoft
• CAA: which certificate authorities may issue SSL certificates for the domain
• SOA: technical details about the DNS zone, including the primary name server and a serial number that changes with each update

How to Read Your Result

Results are grouped by record type. Each record shows its value, its TTL and a short explanation. Where we recognize the service behind a record, we name it, so you can see at a glance that mail goes to Google Workspace, the name servers are at Cloudflare or a TXT record verifies the domain with Microsoft 365.

The What to Know section points out anything worth attention: a broken email record, name servers split across two providers, a domain parked with a parking service, or a missing CAA record. Record types with nothing published are listed in the summary line so you know they were checked.

What TTL Means

TTL, or time to live, is how long other servers may keep a copy of a record before asking for it again. A TTL of 1 hour means a resolver that looked up the record may keep using that answer for up to an hour, even if you change it in the meantime.

Short TTLs, a few minutes, make changes spread quickly but cause more lookups. Long TTLs, a day or more, reduce lookups but slow down changes. Before moving a website or switching email providers, lower the TTL on the records you plan to change a day ahead, then raise it again once the move is done.

DNS Lookup Commands: nslookup and dig

On a computer, you can run the same lookups from the command line. On Windows, macOS and Linux, nslookup example.com shows the A records, and nslookup -type=mx example.com shows the mail servers. On macOS and Linux, dig is more detailed: dig example.com MX shows the mail servers with their TTLs, and adding +short trims the output to just the answers.

Command-line tools ask whichever resolver your computer uses, which may be your internet provider’s or your office’s. The tool above asks Google Public DNS, with Cloudflare as a backup, so it shows what most of the internet sees rather than what your own network has cached.

Common DNS Problems

A few problems come up again and again, and most show up clearly in a lookup:

• A website that won’t load, often because the A record still points to an old server after a move
• Email that stops arriving, usually from MX records left pointing at a previous email provider
• Name servers split between two providers, so visitors get different answers depending on which one they ask
• Two SPF records in TXT, which makes SPF fail for all of the domain’s mail
• A www name that works while the root domain doesn’t, or the other way around, because only one of them has records

Why Your Change Isn’t Showing Yet

If you just changed a record and the lookup still shows the old value, the old answer is probably still cached. Resolvers keep records for up to their TTL, so a record with a TTL of 4 hours can take up to 4 hours to update everywhere.

Changing name servers takes longer, often several hours and sometimes up to two days, because the change has to be published by the registry for the domain’s extension and the old name server records have their own long TTLs. If the lookup shows your new records, the change is live on Google and Cloudflare’s resolvers, which most of the internet relies on.

Root Domains and Host Names

The root domain, such as example.com, is the top of your domain and holds records that apply to the whole domain, like NS, SOA, MX and most TXT records. Host names such as www.example.com or blog.example.com are names under it, and each can have its own A, AAAA or CNAME records.

When you look up a host name, the tool shows the records for that name only. If a host name is an alias, it follows the alias and shows the addresses it finally points to. For a closer look at aliases, including chains and dangling records, use the CNAME Lookup.

Nothing you look up here is saved or linked to you. Lookups run in your browser and go straight to the public DNS resolvers named above.