Key DNS records:
A (IPv4),
AAAA (IPv6),
MX (mail server),
TXT (SPF/DKIM/DMARC/verification),
CNAME (alias),
NS (nameserver),
PTR (reverse lookup),
SOA (zone authority).
TXT records are used for SPF/DKIM/DMARC email security. PTR records verify reverse DNS (email deliverability). CNAME chains should be minimal. dig [domain] [type] queries specific record types. Misconfigured MX records cause email delivery failures.