Query A, AAAA, MX, TXT, NS, SOA, CAA and other DNS records of a domain through Cloudflare or Google public DNS.
DNS & Domains
DNS & Domain Tools
DNS is where most "the site is down" and "the email bounced" stories actually start. These tools query the records a domain publishes — A, AAAA, CNAME, MX, NS, TXT, SOA, PTR, CAA and more — through real public resolvers, compare the answers across resolvers and regions while a change propagates, and read a domain's registration, nameserver and expiry data from the registry's own RDAP service.
The email-authentication checkers go further than fetching a record: they parse SPF, DKIM and DMARC the way a receiving mail server does, count the SPF lookups, follow the includes and report the policy a message would actually be evaluated against. Every page names the resolver or registry it asked, so a result is something you can reproduce with dig or a registrar, not a black box.
Tools in this category
Ask eight public DNS resolvers the same question at once and see whether they return the same records after a DNS change.
DNS & Domains
Ask every authoritative nameserver of a domain directly and check that they answer, are authoritative and serve the same records and SOA serial.
DNS & Domains
Find the PTR host name of an IPv4 or IPv6 address and check that the name resolves back to the same address.
DNS & Domains
List the mail servers (MX records) of a domain in priority order, with the IPv4 and IPv6 addresses each one resolves to.
DNS & Domains
Compare two DNS record sets — live lookups or records pasted from dig or a zone file — and see what is only on one side.
DNS & Domains
Read the registration record of a domain, IP address or AS number from the registry's RDAP service, or its WHOIS text where no RDAP exists.
DNS & Domains
See when up to five domain registrations expire, with the days left and any grace or redemption state, from each registry's RDAP or WHOIS data.
DNS & Domains
Check whether up to five domain names are taken, from the registry's RDAP answer and public DNS together; "likely available" only when both agree.
DNS & Domains
Split host names into public suffix, registrable domain and subdomain with the Public Suffix List, in your browser, and see which rule decided.
DNS & Domains
Follow http://, https://, http://www. and https://www. of a domain and check that all four reach one canonical HTTPS address with permanent redirects.
DNS & Domains
Check a domain's SPF record: follow every include and redirect, count the 10 DNS lookups RFC 7208 allows and find syntax errors.
DNS & Domains
Look up the DKIM public key at selector._domainkey.domain and check its tags, key type and key length against RFC 6376 and RFC 8301.
DNS & Domains
Find the DMARC policy that applies to a domain or subdomain, explain every tag and flag weak settings such as p=none, no reports or pct below 100.
DNS & Domains
See which certificate authorities may issue certificates for a domain: CAA issue, issuewild and iodef records, found by climbing to parent domains.
DNS & Domains
Check whether a domain is protected by DNSSEC: follow the chain of trust from the root through the TLD to the zone and tell signed, unsigned and broken apart.
DNS & Domains