Domain & IP Learning Center
Clear, practical guides for WHOIS, RDAP, DNS, IP networks and website diagnostics.
Each guide links to a live lookup tool, so you can check real DNS and registration data as you read.
DNS Fundamentals
4 guidesWhat Is DNS?
A practical introduction to the system that connects domain names to internet services.
WHOIS vs RDAP vs DNS: What Is the Difference?
Learn what each lookup answers: registration data, structured registry data and live DNS resolution.
IPv4 vs IPv6: What Is the Difference?
Learn why both address families exist and how they appear in DNS.
What Is DNS TTL and DNS Propagation?
Why DNS changes can appear at different times for different users.
DNS Record Types
6 guidesDNS Record Types Explained: A, AAAA, CNAME, MX, TXT, NS & CAA
A practical guide to the DNS records most often used for websites, email and verification.
A and AAAA Records Explained
See how a hostname points to IPv4 and IPv6 addresses.
CNAME Records Explained
Understand hostname aliases, resolution chains and common configuration rules.
Nameservers and NS Records
Understand DNS delegation and why authoritative name servers matter.
SOA Records Explained
Understand the zone metadata that controls serials, refresh intervals and negative caching.
SRV Records Explained
Learn how DNS can advertise the host and port for a service.
Email & Deliverability
3 guidesMX Records and Email Routing
Learn how inbound email finds the mail servers for a domain.
SPF, DKIM and DMARC Explained
Understand the DNS records that help protect a domain from email spoofing.
What Is Reverse DNS (PTR)?
How PTR records map an IP address back to a hostname and why mail systems use them.