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DNS turns a name like
example.com into the addresses and settings that the rest of the internet needs. A domain's settings live in records, and each record type answers one question.The records you'll meet most
Type | Answers | Example value |
A | Which IPv4 address serves this name? | 192.0.2.10 |
AAAA | Which IPv6 address serves this name? | 2001:db8::10 |
CNAME | Which other name should I look up instead? | shop.example-host.com |
MX | Which server receives this domain's email? | 10 mail.example.com |
TXT | What free-form text does this domain publish? | v=spf1 include:_spf.example.com ~all |
NS | Which servers hold this domain's records? | ns1.example-dns.com |
CNAME records
A CNAME points one name at another name, not at an address. Hosting providers often ask for one because it lets them change their own server addresses without asking every customer to update DNS.
Two rules trip people up:
- A name with a CNAME can't have other records of its own.
- The root of a domain (
example.comitself) can't use a plain CNAME. Many DNS providers offer a workaround called CNAME flattening, or an ALIAS record, which looks up the target and answers with its addresses.
TXT records
TXT records hold text that other systems read. The common uses are email rules (SPF, DKIM, DMARC) and proving to a service that you control a domain. A service gives you a value, you publish it, and the service looks it up.
Checking records
dig +short example.com A
dig +short www.example.com CNAME
dig +short example.com MX
dig +short example.com TXTdig asks your resolver, so a change you just made may not show yet. Asking a public resolver directly, for example dig @1.1.1.1 example.com, gives a second opinion.How long changes take
Every record has a TTL, the number of seconds resolvers may keep a cached answer. If a record had a TTL of 3600, some visitors may see the old value for up to an hour after you change it. Lowering the TTL a day before a planned change makes the switch faster.
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