DNS — How Domain Name Resolution Works

DNS translates domain names to IP addresses. One of the most important internet protocols.

How DNS Works¶

Query chain: local cache → OS resolver → recursive DNS → root server → TLD server (.com) → authoritative server.

Record Types¶

• A — IPv4
• AAAA — IPv6
• CNAME — alias
• MX — mail
• TXT — SPF, DKIM, verification
• NS — nameserver
• SRV — service discovery

Commands¶

dig example.com dig example.com MX dig +trace example.com dig @8.8.8.8 example.com

TTL and Caching¶

TTL = how long the resolver caches a response. Low = fast changes, more queries. Typically 300-3600s.

DNSSEC¶

Cryptographic signatures of DNS responses against spoofing.

dig +dnssec example.com

DNS is Fundamental¶

Understanding DNS is essential. Learn dig and the resolution chain.