Computers find each other by numbers. People prefer names. DNS, the Domain Name System, translates between the two, millions of times a second, without anyone noticing.
One lookup, step by step
- 1Those servers answer with the address
- 2The computer asks its resolver, usually run by your internet provider
- 3The resolver asks a root server who handles .com
- 4The .com servers name the servers responsible for example.com
- 5The browser connects to that address
- 6You type example.com and press Enter
The records worth knowing
Record | What it holds | Example value |
|---|---|---|
A | An IPv4 address | 203.0.113.10 |
AAAA | An IPv6 address | 2001:db8::10 |
CNAME | Another name this one is an alias for | shop.example.net |
MX | The servers that receive email | 10 mail.example.com |
TXT | Text, such as SPF rules or ownership proofs | v=spf1 include:... ~all |
NS | The servers responsible for the domain | ns1.example.com |
Look it up yourself
On most computers, a terminal can ask DNS directly.
nslookup -type=MX example.comOr use the Mailbox Provider Checker, which looks up the MX records and names the provider behind them.
Resolvers remember answers for a while (the record's TTL, time to live), which is why a changed record can take hours to reach everyone.
Check what you know with the DNS record types exercise.