DNS (the Domain Name System) is the internet's address book. People remember names like yourdomain.com; computers find each other by numbers called IP addresses. DNS turns the name into the right address, in a fraction of a second, every time someone visits your website or sends you email.
How a lookup works
- Someone types yourdomain.com into a browser, or sends an email to [email protected].
- Their device asks a DNS resolver (usually run by their internet provider) for the answer.
- The resolver asks the internet's root and .com servers which nameservers are in charge of your domain.
- It asks those nameservers for the right record: an A record for a website, an MX record for email.
- The answer comes back and is cached for the record's TTL (time to live), so the next lookup is faster.
That caching is why DNS changes don't show up everywhere at once. Until the old answer's TTL runs out, some people still get it.
Key terms
| Term | Meaning |
|---|---|
| Nameservers | The servers in charge of your domain’s records. Ours are dns1, dns2 and dns3.liberationtek.com. |
| DNS zone | All of the records for one domain. |
| Record | One entry in the zone, such as an A, CNAME, MX or TXT record. |
| TTL | How long, in seconds, other servers may cache a record. 3600 is one hour. |
| Propagation | The time it takes for a change to replace cached answers everywhere. Usually under an hour, up to 48 hours. |
Common records
- A records: point your domain to your website's server.
- CNAME records: point a subdomain such as www to another name.
- MX records: say where your email is delivered.
- TXT records and SPF: prove you own the domain and protect your email.
Ready to make a change? See Managing Your DNS Records.
