WhatIP Learn

Learn About IP Addresses, DNS, VPNs & Network Basics

Clear, practical guides that explain the internet connection details you see in WhatIP without unnecessary technical jargon.

NETWORKING

What Is NAT?

See how Network Address Translation lets multiple devices share a public IPv4 address and how port mapping works.

 NETWORKING

What Is CGNAT?

Understand carrier-grade NAT, shared public IPv4 addresses, and why inbound connections can be difficult.

 IP NETWORKING

CIDR & Subnets

Learn how slash notation describes network prefixes, address blocks, and efficient IP allocation.

 DNS

DNS Record Types

Understand A, AAAA, CNAME, MX, TXT and NS records and what each one is used for.

 DNS

Reverse DNS & PTR

Learn how an IP address can map back to a hostname and why reverse DNS matters.

 REGISTRATION

RDAP vs WHOIS

Compare modern structured registration data with the older WHOIS lookup model.

 ROUTING

BGP & ASN Routing

Understand how autonomous systems exchange routes and why ASN data appears in IP results.

 DNS

DNS TTL & Propagation

Find out why DNS changes can take time and how resolver caching affects what you see.

 SECURITY

IP Reputation & Blacklists

Learn how reputation lists work, why addresses get listed, and how to interpret a result.

 NETWORKING

Anycast IP Addresses

Understand how one IP can be announced from multiple network locations for resilience and routing.

 TRY A TOOL

Run a DNS Lookup

Inspect the public DNS records returned for a domain with the free WhatIP DNS tool.

 TRY A TOOL

Run an ASN Lookup

Explore network ownership and autonomous system information for an IP address.

WhatIP Blog

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