Welcome to our comprehensive guide on DNS (Domain Name System), the backbone of internet navigation. With this cheat sheet, you'll learn about the various DNS record types and key DNS concepts crucial to managing domain names and ensuring seamless internet navigation.
DNS Record Types
A Record (Address Record)
- Maps a hostname to an IPv4 address.
example.com A 192.0.2.1
AAAA Record (IPv6 Address Record)
- Maps a hostname to an IPv6 address.
example.com AAAA 2001:db8::1
CNAME Record (Canonical Name Record)
- Maps an alias name to the true or canonical domain name.
www.example.com CNAME example.com
MX Record (Mail Exchange Record)
- Routes email to the correct mail server.
example.com MX 10 mailserver.example.com
NS Record (Name Server Record)
- Delegates a DNS zone to an authoritative server.
example.com NS ns1.example.com
PTR Record (Pointer Record)
- Provides the reverse DNS lookup, mapping an IPv4 address to a hostname.
18.104.22.168.in-addr.arpa PTR example.com
SOA Record (Start of Authority Record)
- Holds crucial information about the DNS zone.
SRV Record (Service Record)
- Defines the hostname and port number for specific services, like VOIP or IMAP.
TXT Record (Text Record)
- Can contain arbitrary text and also used to define DNS-SEC, SPF, DKIM, and DMARC records.
Key DNS Concepts
A DNS client requires the DNS server to respond with either the requested resource record or an error message if the DNS server cannot find the record.
The DNS server refers the DNS client to another server if it does not have the requested record.
The time it takes for updates to a DNS record to reach all the DNS servers worldwide. This can take anywhere from a few minutes to 48 hours.
A portion of the domain name space that is served by a DNS server.
DNSSEC (DNS Security Extensions)
DNSSEC add security to the DNS protocol by enabling DNS responses to be validated.
Understanding DNS is vital for anyone managing a website or working in IT. This DNS cheat sheet provides a solid foundation, but remember, DNS is a vast topic with many more aspects to explore. Bookmark this page for quick reference and happy learning!