Domains & DNS

Your app answers at 203.0.113.10 - a number nobody will type or trust. A domain turns that number into yourproject.com. The system that maps the name to the number is DNS; if the underlying "names → addresses" machinery is new to you, IP, DNS & Ports explains it from the ground up. Here's the practical sequence to point a fresh domain at your box.

Buy one, then choose who runs its DNS

Buy a domain from any registrar. Cheap and fine for a side project; pick the name, pay, done.

Then decide who answers DNS queries for it. Two options:

• Use the registrar's DNS - add records right there. Simple.
• Point the registrar's nameservers at another DNS provider (very commonly Cloudflare, which is the next phase). You change the nameservers at the registrar to the two the provider gives you; from then on, you manage records at the provider.

$ dig +short NS yourproject.com
amara.ns.cloudflare.com.
rob.ns.cloudflare.com.

What just happened: dig asked which nameservers are authoritative for the domain - here, Cloudflare's. ⚠️ Nameserver changes can take a while to propagate (minutes to a day). If your records "aren't working," confirm the nameservers switched first - nothing else matters until they have.

The two records you need: A and CNAME

• A record maps a name straight to an IP address. Point the apex at your box: yourproject.com → 203.0.113.10.
• CNAME maps a name to another name (an alias). Point www at the apex: www.yourproject.com → yourproject.com.

  Type   Name                  Value
  A      yourproject.com       203.0.113.10
  CNAME  www                   yourproject.com

⚠️ Apex vs www - the apex usually can't be a CNAME

This trips up nearly everyone. The apex (also "root" or "naked" domain - yourproject.com with no subdomain) cannot, by the DNS spec, be a CNAME. Only an A record (or AAAA for IPv6) works at the apex. So:

• apex (yourproject.com) → A record → your IP.
• www (www.yourproject.com) → CNAME → the apex.

⚠️ Many DNS providers (Cloudflare included) offer CNAME flattening that lets you put a CNAME-like record at the apex by resolving it to an IP behind the scenes - handy, but if your provider doesn't, remember: apex = A record. Decide which one is canonical (most pick the apex, redirecting www → it, or vice versa) and be consistent, so links and cookies don't split across two hostnames.

⚠️ .dev (and .app) are HTTPS-only

If you bought a .dev domain because it's cute - know this before you lose an hour: .dev and .app are on the browser HSTS preload list, which means browsers refuse to load them over plain http:// at all. There's no "I'll add HTTPS later" with a .dev; until HTTPS works, the site simply won't open - not a warning, a hard fail. That's fine, because HTTPS is the very next phase - just don't panic when http://yourproject.dev looks dead. (On a .com you'd see it over http first; on .dev you won't.)

Recap

1. Buy a domain, then either use the registrar's DNS or point its nameservers at a DNS provider (often Cloudflare - next phase). Confirm the nameserver switch with dig NS before debugging anything else.
2. A record → name to IP (use it for the apex). CNAME → name to name (use it for www).
3. ⚠️ The apex can't be a CNAME - it needs an A record (unless your provider does CNAME flattening).
4. ⚠️ .dev/.app won't load over HTTP at all - they're HTTPS-only, so the site looks broken until the next phase is done.

The name resolves to your box. Now make it HTTPS, safe, and fast - with Cloudflare.

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