DNS, Hosting & Domains

1.7.1Definitions

A domain name is the human-readable address of a site (example.com), registered through a domain registrar. DNS (Domain Name System) is the internet's directory service, translating that domain name into the numeric IP address a browser actually needs to connect. Hosting is the service that keeps a product's files or application running and reachable on a server, at that IP address, continuously.

1.7.2Why This Layer Exists

Computers address each other by number, not name — but numbers are unmemorable and can change when infrastructure changes. DNS exists as an indirection layer: a stable, human-readable name pointing at a numeric address that can be updated behind the scenes without anyone needing to learn a new address. Domain registration exists to make names globally unique and prevent conflicting ownership claims. Hosting exists because a server needs to run continuously, with power, connectivity, and maintenance the average person or team is not equipped to provide from their own premises.

1.7.3Key DNS Record Types

• A record — points a domain directly to an IPv4 address.
• CNAME — points a domain to another domain name rather than a raw IP, useful for pointing subdomains at third-party services.
• MX record — directs email for the domain to the correct mail servers.
• TXT record — holds arbitrary text, commonly used for domain ownership verification and email security (SPF/DKIM).

1.7.4Common Mistakes

• Underestimating DNS propagation time. Changes to DNS records aren't instant everywhere — cached copies of old records ("time to live") can persist elsewhere for hours, causing confusing, inconsistent behavior right after a change.
• Letting a domain registration lapse. A forgotten renewal can take an entire product offline and, in the worst case, allow the domain to be re-registered by someone else entirely.
• Conflating the domain registrar and the host. These are frequently different companies serving different roles; confusing them leads to looking in the wrong place when something breaks.

1.7.5Best Practices

• Enable auto-renewal on domain registrations and keep registration contact information current.
• Lower a DNS record's TTL in advance of a planned change, so the change propagates faster when it actually happens.
• Keep a record of which registrar and which host are in use for each domain — this is easy to lose track of across a long product lifetime.