Glossary

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 Record
  A DNS record that maps a domain name to an IPv4 address, telling browsers which server to contact for that name.
• Amortization
  The 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 Subnetting
  A 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 Record
  A 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 Record
  A 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 Address
  A numeric label assigned to every device on a network so data can be routed to and from the correct destination across the internet.
• IPv4
  The fourth version of the Internet Protocol, using 32-bit addresses written as four numbers separated by dots, such as 203.0.113.42.
• IPv6
  The newest version of the Internet Protocol, using 128-bit addresses to provide a vastly larger pool than IPv4 can offer.
• MX Record
  A 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 Server
  An 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.