DNS Terminology

Core DNS concepts, hierarchy entry points, resolvers, caching, and domain structure.

• DNS
• Root Servers
• TLD
• Registry
• Registrar
• Apex / Zone Apex
• Subdomain
• TTL
• Propagation
• Recursive Resolver
• Public Resolver
• Local Resolver
• Authoritative Answer

How parent zones hand off domains to authoritative nameservers, including glue and bailiwick.

• NS Record
• Delegation
• Referral
• Parent Zone
• Child Zone
• Authoritative Nameserver
• Nameserver Hostname
• Nameserver Address
• Glue
• In-Bailiwick
• Out-Of-Bailiwick
• Lame Delegation

Zone data, SOA serials, primary/secondary nameservers, and zone transfers.

• SOA Serial
• SOA Record
• Primary Nameserver
• Secondary Nameserver
• Zone File
• AXFR / Zone Transfer
• IXFR

Common DNS record types used by websites, mail routing, verification, and reverse DNS.

• A Record
• AAAA Record
• CNAME Record
• MX Record
• TXT Record
• CAA Record
• PTR / Reverse DNS
• Wildcard Record
• CNAME Flattening / ALIAS / ANAME

DNS terms related to SPF, DKIM, DMARC, and email authentication records.

• SPF
• DKIM
• DMARC
• Forward Confirmed Reverse DNS
• Alignment
• BIMI
• MTA-STS
• TLS-RPT

DNS response codes, cache behaviour, EDNS, UDP, TCP, and encrypted DNS transport.

• NXDOMAIN
• SERVFAIL
• Negative Caching
• Resolver Cache
• EDNS
• Truncated Response
• DNS Over TCP

DNSSEC, split DNS, dangling DNS, anycast, GeoDNS, and encrypted resolver protocols.

• DNSSEC
• DS Record
• DNSKEY Record
• RRSIG Records
• AD Flag
• Split-Horizon DNS
• Dangling DNS
• Anycast DNS
• GeoDNS
• DoH / DNS Over HTTPS
• DoT / DNS Over TLS