DNS records
DNS records are the entries that map a domain to addresses and services: A and AAAA for hosts, MX for mail, NS for the authoritative servers.
DNS records map a domain to addresses and services. A and AAAA point at hosts, MX points at mail servers, NS names the authoritative servers, and TXT carries everything the system was never designed for.
The ones worth watching on a domain you own:
| Record | Answers |
|---|---|
A / AAAA | which host serves the site |
NS | which servers are authoritative, which is who controls the name in practice |
MX | where mail goes |
TXT (SPF) | which servers may send mail as this domain |
TXT (_dmarc) | what receivers should do with mail that fails checks |
DNSSEC | whether answers are signed |
What Domduck records
The self_dns source reads A, AAAA, MX, NS, SPF, DMARC and DNSSEC state once a day through a fixed resolver over HTTPS. Every reading is stored, so a record change is an event with a date on it.
The resolver is fixed rather than derived from the domain, which is why this source needs no network guard: the request always goes to the same server, and the domain is only ever a query string in it.
Why it matters
A nameserver change is the highest-stakes event on this list. Whoever the NS records point at controls the whole name: mail, certificates issued by DNS validation, and every subdomain. A change nobody made is an incident, and a change nobody recorded is impossible to date afterwards.
SPF and DMARC belong to email deliverability rather than search, which is the other meaning of the phrase domain reputation. Domduck records them because they are part of the public record for the domain, not because they move a ranking.
Related
- TLS certificateA TLS certificate is the signed file a site presents to prove it owns its name, naming the domains it covers and the dates it is valid between.
- Domain reputation vs IP reputationDomain reputation follows the name and travels with it. IP reputation follows the address and resets when you move server.
Primary source: IANA DNS parameter registry