DNS setup for _dmarc.github.org.
Pick where your site or email lives: get the exact records it asks for, and see which ones your domain already has.
Looking up…
How to use it.
- Pick the platform where your website or email lives, and type your domain.
- Add each record marked Missing or Different at your DNS host (usually where you bought the domain), exactly as shown: the copy buttons copy one value each.
- Delete the records listed under To remove: a second A record or an old mail server sends some visitors or mail to the wrong place.
- Come back and check again: each record turns to In place as resolvers pick it up.
Reading the states.
- In place: the value matches the platform's guide. Via ALIAS: the domain answers with the same addresses as the name it should point to, which is how flattening works.
- Different value: something else is there. If the site already works, the platform may have given you its own value; check its dashboard.
- Older value: a value the platform used before and still accepts. Behind Cloudflare: the name is proxied, so its record cannot be seen from outside.
- Values in angle brackets, such as a project's own CNAME or a verification code, come from the platform's dashboard; the check only confirms their shape.
Questions people ask.
Which DNS records connect a domain to a website?
Usually an A record on the domain itself (@) and a CNAME record on www, with values that depend on the platform. Pick yours and the page lists them from the platform's own guide, then checks your domain.
What does @ mean?
The domain itself, without www or anything in front: example.com rather than www.example.com. Some DNS hosts want the field left empty instead.
Why can't the domain itself have a CNAME?
DNS forbids a CNAME next to other records (RFC 1034, section 3.6.2), and the domain itself always has its NS and SOA records. That is why platforms give A records for it, or ask for ALIAS, ANAME or CNAME flattening where the DNS host offers it.
How long until the change works?
Resolvers keep the old answer until its TTL runs out, usually minutes to an hour; some platforms quote up to 24 to 72 hours for the rare slow case. The DNS propagation checker shows who has the new value.
Can one domain have a website and email at different places?
Yes. Website records (A on @, CNAME on www) and email records (MX and the SPF TXT on @) sit side by side. Only replace records of the same type and name that the new platform asks for.
What does Behind Cloudflare mean?
The name is proxied by Cloudflare (orange cloud), so DNS answers with Cloudflare's addresses and hides the record behind them. Check that record in the Cloudflare dashboard instead.
Hivex index
Short names, still free to register.
Starting something new? Hivex keeps a live index of short, brandable .si names nobody has claimed yet, each checked with the registry.
From code, or an AI assistant.
Hivex's free JSON API and MCP server check domains, DNS and registration records from your own code or from AI assistants that speak MCP. No key needed.
More DNS tools
- DNS lookupAll records at once: A, AAAA, CNAME, MX, NS, TXT, CAA, SOA.
- MX lookupMail servers in priority order, the provider, SPF and DMARC at a glance.
- NS lookupName servers, the DNS host, SOA settings, and marketplace parking.
- TXT lookupSPF, DMARC, DKIM and verification tokens, joined and labelled.
- CNAME lookupThe full alias chain, the final addresses, and the platform behind it.
- CAA lookupAllowed certificate authorities, wildcard rules and report addresses.
- DNS propagation checker13 public resolvers side by side, with how long each keeps its copy.
- Reverse DNSThe PTR hostname of an IPv4 or IPv6 address, checked both ways.
- DNS health checkEvery name server asked directly: one report, every check.
- DNSSEC checkerDS, keys and validation: where the chain of trust holds or breaks.
- Subdomain finderSubdomains from certificate logs, DNS and the archive.
- DNS historyPast IP addresses and hosts, from passive DNS.
- Domain checkerIs a name free to register? Checked live on any extension.
Sources
- RFC 1034: Domain names: concepts and facilities (the CNAME rule, section 3.6.2)
- RFC 7208: Sender Policy Framework (SPF)
- RFC 6376: DomainKeys Identified Mail (DKIM)
By Hivex. Updated 11 October 2026. Records come from each platform's own guide; your domain's DNS is read live through Cloudflare's public resolver. Nothing is stored.