DNS check: test every DNS record of a domain
Enter a domain and instantly see its A, AAAA, MX, NS, TXT, SOA and CAA records – with a clear assessment and tips on what to improve.
Look up DNS records
Enter a domain or subdomain, for example your-domain.co.uk or www.your-domain.co.uk.
Lookups run through the Quad9 DNS resolver (Switzerland). We keep the checked domain and an anonymised IP address for no longer than 30 days.
How DNS works
What is DNS?
The Domain Name System translates names such as hosttest.co.uk into the IP addresses computers need to find each other. When you open a website, your device first asks a resolver, usually your internet provider's. It works its way from the root servers via the servers of the extension, such as .uk, to the domain's nameservers and remembers the answer for the length of the TTL.
The most important DNS records
A and AAAA point to the IPv4 and IPv6 address of your server. CNAME makes one name an alias of another. MX defines which servers accept your email. NS names the responsible nameservers, and SOA holds the zone's master data. TXT records contain SPF and verifications for Google or Microsoft, among other things, and CAA decides which certificate authorities may issue SSL certificates for your domain.
What the TTL means
Every record has a time to live in seconds. That is how long resolvers may cache the answer. A TTL of 3600 means it can take up to an hour after a change before everyone sees the new address. If you are planning a move, lower the TTL to 300 seconds a day or two beforehand and raise it again afterwards.
Common DNS mistakes
No IPv6 record
Without an AAAA record your site can only be reached via IPv4. That works, but a growing share of users browse via IPv6. Ask your host for an IPv6 address.
Mail servers without SPF and DMARC
If your domain has MX records but neither SPF nor DMARC, others can easily forge email in your name. Large providers such as Gmail then also file your genuine email as spam more often.
Old records after a move
After changing host, A or MX records often still point to the old server. Check every record after each move and delete whatever you no longer need.
Frequently asked questions
Enter your domain above and click Check. The DNS check looks up every common record type and assesses it. For details on email records, aliases or nameservers, switch straight to the MX, SPF, DMARC, CNAME or nameserver check.
Resolvers cache answers for the length of the TTL. Until the old answer expires, some users still see the old state. Our result shows what public resolvers are serving right now – they too may still have an old answer in their cache. Whether your nameservers already have the new state is shown by the nameserver check via the SOA serial.
An A record points directly to an IP address. A CNAME points to another name, whose address is then used. CNAMEs are handy for services such as shops or CDNs whose IP may change. They are not allowed on the main domain itself, though.
The start of authority holds a zone's master data: the primary nameserver, the contact address and a serial number that rises with every change. That is how the other nameservers know whether they need to load a new version of the zone.
It is not mandatory. With CAA you decide which certificate authorities, such as Let's Encrypt, may issue SSL certificates for your domain. This makes it harder for attackers to obtain a certificate for your domain.
No. The DNS check and all its sub-tools are free and need no sign-up. To keep them fast for everyone, they are limited to 20 checks per hour.
