Glossary
DNS
NS record
Names an authoritative nameserver for a zone. It appears in two places — the parent zone as a delegation, and the zone itself — and a mismatch between them is a common and long-lived misconfiguration.
Defined in RFC 1035 §3.3.11.
Where this appears
The lessons that use this term, and what each is for.
Advanced Email TrustForward-confirmed reverse DNSVerify that a sending host names itself consistently in three places, and fix it when it does not.Domain Security FundamentalsZones, delegation and glueFind the two places a domain’s NS records live and say what happens when they disagree.Domain Security FundamentalsThe records worth knowing, field by fieldRead a zone’s SOA, NS, A, CNAME, MX, TXT and CAA records and say what each asserts.DNS Security PractitionerOne provider is one outageQuantify what a single authoritative provider means for every service you run.DNS Security PractitionerRunning twoSay what must stay synchronised across two providers, and what DNSSEC adds to that.DNS Security PractitionerThree kinds of danglingRank a dangling CNAME, NS and MX by what each one hands an attacker.Domain Abuse & ImpersonationReuse across a setLink separate registrations into one campaign from shared infrastructure.Domain Abuse & ImpersonationHosting patternsRead hosting choices as evidence, and say where that evidence stops.Brand ProtectionWatching your own estateDetect an unauthorised change to your own records before anybody outside does.