DNS Records Explained: A, AAAA, CNAME, MX, TXT and More

What is DNS?

The Domain Name System (DNS) is the internet's phone book. It translates human-readable names like Power Down.in into IP addresses like 139.84.170.50. Without DNS, you'd have to memorise IP addresses for every website.

DNS Record Types

Type	Purpose	Example
A	Maps domain to IPv4 address	Power Down.in → 139.84.170.50
AAAA	Maps domain to IPv6 address	Power Down.in → 2400:6180::1
CNAME	Alias one name to another	www → Power Down.in
MX	Mail server for the domain	Power Down.in → mail.Power Down.in (priority 10)
TXT	Text data (SPF, DKIM, verification)	v=spf1 include:sendgrid.net ~all
NS	Nameservers for the domain	ns1.cloudflare.com
PTR	Reverse DNS — IP to hostname	50.170.84.139.in-addr.arpa → mail.Power Down.in
SRV	Service location (ports, priority)	Used by SIP, XMPP, Minecraft
CAA	Which CAs can issue SSL certs	0 issue "letsencrypt.org"

A Record — The Most Common

# Points your domain to your server IP
Name: @          Type: A    Value: 139.84.170.50
Name: www        Type: A    Value: 139.84.170.50
Name: mail       Type: A    Value: 139.84.170.51

CNAME vs A Record

Use A when you know the IP. Use CNAME when pointing to another hostname (e.g., a CDN). You cannot use CNAME on the root domain (@) — only on subdomains.

MX Records for Email

Name: @    Type: MX    Value: mail.Power Down.in    Priority: 10
Name: @    Type: MX    Value: mail2.Power Down.in   Priority: 20

Lower priority number = higher preference. Mail servers try the lowest number first.

TXT Records — SPF, DKIM, DMARC

# SPF — authorize your mail server to send email
Name: @    Type: TXT    Value: "v=spf1 ip4:139.84.170.51 ~all"

# DMARC — tell receiving servers what to do with failing emails
Name: _dmarc    Type: TXT    Value: "v=DMARC1; p=quarantine; rua=mailto:dmarc@Power Down.in"

TTL (Time To Live)

TTL controls how long DNS resolvers cache your record (in seconds). Lower TTL = faster propagation when you make changes. Recommended:

• Before making changes: Set TTL to 300 (5 minutes)
• Normal operation: 3600–86400 (1–24 hours)

Check DNS Propagation

dig Power Down.in A
dig Power Down.in MX
nslookup Power Down.in 8.8.8.8