DNS Checker

The Domain Name System translates human-readable names into the addresses and settings that computers use. This tool queries public DNS for the most important record types of a domain and shows them in a single table with their TTL values.

On top of the raw data, it checks common problems that break websites and email: missing name servers, no mail servers, missing IPv6, an MX record pointing to an IP address, or no SPF and DMARC records.

• A and AAAA — the IPv4 and IPv6 addresses where the domain’s website or service runs.
• CNAME — makes a name an alias of another name; common for www and third-party services.
• MX — the mail servers that receive email for the domain, ordered by priority (lower first).
• NS — the authoritative name servers that host the domain’s DNS zone.
• TXT — text records used for SPF, DMARC, domain verification and other settings.
• SOA — the start of authority: primary name server, administrator mailbox, serial number and timers.
• CAA — the certificate authorities that are allowed to issue TLS certificates for the domain.

• Domain does not resolve — a typo, an expired registration or name servers that are not set at the registrar.
• A single name server — if it goes down the whole domain disappears; always use at least two.
• No MX records — messages sent to the domain bounce. Publish a null MX if the domain should never receive mail.
• Changes not visible yet — resolvers cache answers for the TTL of the old record, so updates can take minutes to hours.

DNS is also where email authentication lives. After the general lookup, validate the details with our SPF, DKIM and DMARC checkers, then send a message to a temporary TempBox address to see how receivers actually evaluate your mail.