Glossary
Plain-English definitions of the IP, DNS, networking, and personal-finance terms used across WhatIP.
18 terms explained in clear language, each linked to the tools and calculators where they matter. Use these as a quick reference or a starting point for the in-depth guides.
- A RecordA DNS record that maps a domain name to an IPv4 address, telling browsers which server to contact for that name.
- AmortizationThe process of paying off a loan through regular fixed payments that gradually shift from mostly interest to mostly principal over time.
- Annual Percentage Rate (APR)The yearly cost of borrowing money expressed as a percentage, including interest and many mandatory fees, so loans can be compared fairly.
- Autonomous System Number (ASN)A globally unique number identifying a network or group of IP ranges under a single administrative control, used for internet routing.
- CIDR and SubnettingA method of writing IP ranges using a slash and prefix length, like 192.168.1.0/24, to define how addresses are grouped into networks.
- CNAME RecordA DNS record that makes one domain name an alias of another, so lookups follow the alias to the target's records.
- DNS (Domain Name System)The internet system that translates human-friendly domain names like example.com into the numeric IP addresses computers use to connect.
- DNS over HTTPS (DoH)A protocol that sends DNS queries inside encrypted HTTPS connections, hiding lookups from network observers and protecting them from tampering.
- DNS RecordA single entry in a domain's DNS zone that tells resolvers how to handle a name, such as which IP address or mail server it maps to.
- IP AddressA numeric label assigned to every device on a network so data can be routed to and from the correct destination across the internet.
- IPv4The fourth version of the Internet Protocol, using 32-bit addresses written as four numbers separated by dots, such as 203.0.113.42.
- IPv6The newest version of the Internet Protocol, using 128-bit addresses to provide a vastly larger pool than IPv4 can offer.
- MX RecordA DNS record that specifies which mail servers accept email for a domain, along with a priority value that orders them.
- Network Address Translation (NAT)A technique that lets many devices on a private network share a single public IP address by rewriting address information in passing traffic.
- Proxy ServerAn intermediary server that forwards requests between a client and a destination, often used to hide the client's IP, filter traffic, or cache content.
- PTR Record (Reverse DNS)A DNS record that maps an IP address back to a hostname, enabling reverse lookups commonly used to verify mail servers.
- TTL (Time To Live)A value that sets how long a piece of data, such as a DNS record or a network packet, remains valid before it is refreshed or discarded.
- Virtual Private Network (VPN)A service that encrypts your internet traffic and routes it through a remote server, masking your real IP address and protecting data in transit.