DNS Management: How Domain Names Work
The Domain Name System (DNS) is the internet's phone book — it translates human-readable domain names (example.com) into IP addresses that computers use to communicate. Understanding DNS helps you manage your domain configuration, diagnose connectivity issues, and understand the implications of DNS changes.
DNS Record Types
- A record: Maps a domain to an IPv4 address — the most common record type
- AAAA record: Maps a domain to an IPv6 address
- CNAME record: Alias — maps a domain to another domain name. Used for subdomains pointing to CDN or load balancer hostnames.
- MX record: Mail server — tells email servers where to deliver mail for your domain
- TXT record: Text data — used for domain verification (Google Search Console, email authentication) and SPF records
- NS record: Name servers — defines which DNS servers are authoritative for your domain
- SOA record: Start of Authority — administrative information about the zone
TTL (Time to Live)
TTL defines how long DNS resolvers cache a record before re-querying. Short TTLs (60 seconds) enable rapid failover — changes propagate quickly. Long TTLs (86400 seconds / 24 hours) reduce DNS query load but slow down changes. Before planned changes (migrations, IP changes), reduce TTL well in advance so changes propagate quickly when made.
DNS Propagation
DNS changes do not take effect everywhere simultaneously. Changes propagate as existing cached records expire. "DNS propagation" takes time proportional to existing TTL values — from minutes to 48 hours for very high TTL records.