DNS Record Types Reference

A records map domain names to IPv4 addresses (like 93.184.216.34). AAAA records map to IPv6 addresses (like 2606:2800:220:1:248:1893:25c8:1946). Both serve the same purpose - pointing a domain to an IP - but for different IP versions.

RFC 1912 prohibits CNAME records coexisting with other records at the same name. Since the root domain must have SOA and NS records, a CNAME would violate this rule. Use ALIAS/ANAME (provider-specific) or an A record at the root instead.

MX records specify mail servers for a domain. The priority value (lower = higher priority) determines delivery order. If priority 10 fails, the sender tries priority 20, and so on. Multiple servers with the same priority get load-balanced between them. Always have a backup MX record for redundancy.

SOA (Start of Authority) is a mandatory record in every DNS zone. It contains the primary nameserver, admin email, serial number (for tracking zone updates), refresh/retry intervals, and expiry time. Zone transfers between DNS servers depend on the serial number to detect changes.

DNS changes don't propagate instantly — they depend on the TTL (Time to Live) set on each record. If your old record had a TTL of 86400 seconds (24 hours), caches worldwide may serve the old value for up to 24 hours. Lower TTL before making changes (e.g., 300 seconds) to speed up propagation globally.

DNSSEC (DNS Security Extensions) adds cryptographic signatures to DNS records (via RRSIG, DNSKEY, DS, NSEC records). It prevents DNS spoofing and cache poisoning by proving records are authentic. Modern registrars and DNS providers increasingly support it.