What Is DNS?
Understanding DNS (Domain Name System) and domain resolution
Table of Contents
What Is DNS?
DNS (Domain Name System) is a distributed system that translates domain names (example.com) to IP addresses (192.0.2.1) and other information. DNS enables computers to find servers and services on the internet using human-readable domain names instead of numeric IP addresses.
DNS records store information about domains including: A records (IPv4 addresses), AAAA records (IPv6 addresses), MX records (mail servers), TXT records (text data, SPF, DKIM, DMARC), CNAME records (aliases), NS records (name servers), and SOA records (zone information). DNS is essential for internet communication, email delivery, and domain management.
Learn more about how DNS lookup works and use our DNS lookup tools to check DNS records.
How DNS Works
1. DNS Query
When you type a domain name (example.com) in a browser or email client, a DNS query is sent to resolve the domain name to an IP address.
2. DNS Servers
DNS queries are processed by DNS servers (recursive resolvers, root servers, TLD servers, authoritative name servers) in a hierarchical system.
3. DNS Resolution
DNS servers resolve domain names by looking up DNS records, starting from root servers and working down to authoritative name servers.
4. DNS Response
DNS servers return DNS records (IP addresses, mail servers, etc.) in response to DNS queries.
5. Caching
DNS responses are cached to improve performance and reduce DNS query load.
6. Domain Resolution
Domain names are resolved to IP addresses, allowing computers to connect to servers using domain names.
DNS Records
DNS records store information about domains:
A Records
A records map domain names to IPv4 addresses (e.g., example.com → 192.0.2.1).
AAAA Records
AAAA records map domain names to IPv6 addresses. Learn more about AAAA records.
MX Records
MX records specify mail servers for email delivery. Check MX records.
TXT Records
TXT records store text data, including SPF, DKIM, DMARC records. Learn more about TXT records.
CNAME Records
CNAME records create aliases, pointing one domain name to another.
NS Records
NS records specify name servers for domains.
SOA Records
SOA records provide zone information. Learn more about SOA records.
DNS for Email
MX Records
MX records specify mail servers for email delivery. Email servers use MX records to find mail servers for recipient domains.
SPF Records (TXT)
SPF records are stored as TXT records and specify authorized mail servers. Check SPF records.
DKIM Records (TXT)
DKIM public keys are stored as TXT records. Check DKIM records.
DMARC Records (TXT)
DMARC policies are stored as TXT records. Check DMARC records.
DNS and Email Delivery
DNS is essential for email delivery, as email servers use DNS to find mail servers and verify authentication records.
DNS Lookup
What Is DNS Lookup?
DNS lookup is the process of querying DNS servers to retrieve DNS records for a domain name. Learn more about how DNS lookup works.
DNS Lookup Tools
Use DNS lookup tools to query DNS records and retrieve DNS information for domains.
Common DNS Lookups
- A record lookup (IPv4 addresses)
- AAAA record lookup (IPv6 addresses)
- MX record lookup (mail servers)
- TXT record lookup (SPF, DKIM, DMARC)
- CNAME record lookup (aliases)
DNS Lookup Uses
DNS lookup is used for: email delivery (MX records), email authentication (SPF, DKIM, DMARC), domain resolution (A, AAAA records), and domain management (NS, SOA records).
