How To Write Domain

Domain names are simpler than most people think, but getting them wrong can waste you hours and money

I've been dealing with domain registration, DNS configuration, and the occasional nightmare of losing a domain because I didn't catch a renewal notification. This guide covers how to properly write and register a domain, with some of the messier details most tutorials skip over. A domain name follows a strict structure. It has a label, a dot, a top-level domain (TLD), and optionally more labels for subdomains. The full form looks like this: label.tld or subdomain.label.tld. That's it. Nothing fancy. The label portion can contain lowercase letters (a-z), digits (0-9), and hyphens. Hyphens can't appear at the beginning or end of a label. Labels are limited to 63 characters each, and the entire domain can't exceed 253 characters. Unicode characters aren't allowed in the standard ASCII representation, which is why IDN (internationalized domain names) exist as a separate encoding scheme.

Here's something most people don't know: the final dot. Technically, a fully qualified domain name ends with a dot, like example.com. That trailing dot represents the root of the DNS hierarchy. Most browsers and applications strip it for display, but if you're writing DNS records or working with tools that expect FQDNs, that dot matters. I once had a script fail silently for three days because I was passing mail.example.com instead of mail.example.com. The trailing dot tells DNS resolvers not to append the search domain. Worth keeping in mind if your tools start resolving things to weird places.

Registering a domain

Pick a registrar. Common ones include Namecheap, Cloudflare Registrar, GoDaddy, and Porkbun. The price for a standard .com registration varies between $8 and $15 per year depending on the registrar and whether they're running a promo. Cloudflare's registrar charges wholesale pricing, which is usually the best deal unless you specifically need features from another provider. During registration, you'll need to provide contact information. ICANN requires valid WHOIS data, though many registrars offer privacy protection services that replace your real address with theirs. I'd recommend using it. The amount of spam and scam emails you'll get without it is absurd. After registration, the domain needs to point somewhere. That's DNS. Most registrars provide basic name servers out of the box, which resolve to a placeholder page. If you're hosting a website, you'll need to configure the records yourself.

DNS records you actually need

The most important record is the A record, which maps a domain to an IPv4 address. For example: @ IN A 192.0.2.45 The @ symbol refers to the root of the domain. If you want a subdomain like www, you'd create a separate A or CNAME record for that.

Then there's the CNAME record, which points one domain to another. A common setup is having www.example.com CNAME to example.com, or pointing it directly to your hosting provider's domain. CNAME records can't coexist with other records at the same name, which trips people up occasionally. You can't have a CNAME and an MX record for the same subdomain. MX records handle email routing. They look like this: @ IN MX 10 mail.example.com.

The number before the mail server is the priority. Lower numbers win. If your primary mail server goes down, the resolver tries the next one. A correctly configured domain usually has two MX records with different priorities. TXT records serve multiple purposes. SPF records prevent email spoofing by listing which servers can send mail on your behalf. DKIM adds cryptographic signatures to outgoing emails. DMARC tells receiving servers what to do when SPF or DKIM checks fail. These are critical if you actually send email, and most mail providers will reject your messages without them. Here's a specific edge case I ran into: I set up SPF for a client's domain with the standard v=spf1 include:_spf.google.com ~all record. Their existing MX records pointed to a third-party spam filter, but the SPF didn't include that filter's IP range. The spam filter was rejecting their own legitimate emails because it was adding headers that looked like third-party modifications. I had to add the spam filter's SPF mechanism explicitly and switch the qualifier from ~all to ?all. Took about twenty minutes to diagnose after two days of the client calling in panic.

Nameservers and where DNS lives

Your registrar doesn't have to handle your DNS. You can point your domain's nameservers to any provider. Cloudflare, Route53, AWS, Cloudns, and several others offer DNS hosting. The advantage of separating the two is that you can switch registrars without touching your DNS, or move DNS providers without losing the domain. When you change nameservers, there's a propagation period. TTL (time to live) values on your old records determine how long cached responses persist. If your old TTL was 86400 seconds, changes could take up to 24 hours to fully propagate. I usually advise setting TTL to 300 (5 minutes) for active domains before making any changes, then reverting it afterward. Saves you from waiting around wondering why things aren't working yet.

Common pitfalls

Don't use a domain registrar that locks your domain during transfers. Some registrars make it nearly impossible to move your domain elsewhere by requiring a password, additional verification steps, or simply ignoring your transfer requests. Cloudflare and Namecheap are generally straightforward about this. Avoid registrars with questionable reputations in transfer practices. Auto-renewal is cheap insurance. I lost a domain once because I misread the renewal date. It was sitting there for a week in redemption period before I noticed, and it cost me $80 to recover instead of the usual $12 renewal fee. Set auto-renew and keep your payment method updated. The ten minutes it takes to configure it will save you significant stress later. Another thing: avoid buying domains with numbers or hyphens unless absolutely necessary. They're harder to communicate verbally, they look unprofessional in most contexts, and people will mistype them constantly. I've seen projects fail partly because the domain was unintelligible over the phone.

What this approach doesn't cover

This guide handles the basics of domain writing and setup. It doesn't cover advanced DNSSEC configuration, wildcard certificates, or multilabel authoritative zones. If you're running a high-traffic site or need enterprise-grade DNS redundancy, you'll want to look into AWS Route53 or Cloudflare's enterprise offerings. The free tiers work fine for personal projects, but they have limitations on query volume and zone complexity that matter at scale. Also worth noting: this process assumes you're dealing with standard public DNS. If you're working in a private network environment, corporate intranets, or internal tooling, the rules are entirely different and usually controlled by whoever manages your infrastructure. Good luck with that.

Quick reference for a standard domain setup

A basic working configuration for a website hosted at IP 192.0.2.45 with Google Workspace for email: www IN A 192.0.2.45
@ IN A 192.0.2.45
@ IN MX 10 ASPMX.L.GOOGLE.COM.
@ IN MX 20 ALT1.ASPMX.L.GOOGLE.COM.
@ IN MX 30 ALT2.ASPMX.L.GOOGLE.COM.
@ IN TXT "v=spf1 include:_spf.google.com ~all" Adjust the IP, mail servers, and SPF mechanism based on your actual setup. This is a template, not a copy-paste solution.