Network Glossary
Essential terms and concepts for IP networking, DNS, and internet protocols
IP Addressing
Terms related to IP addresses and addressing schemes
IPv4
Internet Protocol version 4, a 32-bit addressing system using dotted decimal notation.
IPv6
Internet Protocol version 6, a 128-bit addressing system designed to replace IPv4.
Private IP Address
IP addresses reserved for use within private networks, not routable on the public internet.
Public IP Address
Globally unique IP addresses that are routable on the public internet.
Static IP Address
An IP address that is manually configured and remains constant over time.
Dynamic IP Address
An IP address that is automatically assigned by DHCP and may change over time.
Loopback Address
A special IP address that routes traffic back to the same device.
Subnetting & Routing
Concepts related to network subdivision and traffic routing
Subnet
A logical subdivision of an IP network, created by dividing a larger network.
Subnet Mask
A 32-bit number that divides an IP address into network and host portions.
CIDR (Classless Inter-Domain Routing)
A method for allocating IP addresses and routing that replaces the old classful system.
Default Gateway
The router IP address that devices use to access networks outside their local subnet.
Broadcast Address
The last address in a subnet, used to send packets to all devices in that network.
Network Address
The first address in a subnet, representing the network itself, with all host bits set to zero.
DNS & Domain Names
Domain Name System and related terminology
DNS (Domain Name System)
A hierarchical distributed naming system that translates domain names to IP addresses.
A Record
DNS record type that maps a domain name to an IPv4 address.
AAAA Record
DNS record type that maps a domain name to an IPv6 address.
CNAME Record
DNS record that creates an alias from one domain name to another.
MX Record
DNS record that specifies mail servers responsible for accepting email for a domain.
TXT Record
DNS record that holds arbitrary text data, often used for verification and email security.
TTL (Time To Live)
The duration in seconds that a DNS record can be cached before it must be refreshed.
Nameserver
A server that stores DNS records and responds to DNS queries.
Network Protocols
Communication protocols and standards
TCP (Transmission Control Protocol)
A connection-oriented protocol that ensures reliable, ordered delivery of data.
UDP (User Datagram Protocol)
A connectionless protocol that sends data without guaranteeing delivery or order.
DHCP (Dynamic Host Configuration Protocol)
A protocol that automatically assigns IP addresses and network configuration to devices.
HTTP (Hypertext Transfer Protocol)
The foundation protocol for data communication on the World Wide Web.
HTTPS (HTTP Secure)
An extension of HTTP that uses encryption to secure communication.
NAT (Network Address Translation)
A method of mapping private IP addresses to public IP addresses for internet access.
Network Security
Security concepts and mechanisms
Firewall
A network security system that monitors and controls incoming and outgoing traffic.
VPN (Virtual Private Network)
An encrypted tunnel that provides secure communication over public networks.
SSL/TLS
Cryptographic protocols that provide secure communication over computer networks.
DDoS (Distributed Denial of Service)
An attack that overwhelms a target with traffic from multiple sources.
Quick Reference
IP Addressing
- • IPv4: 32-bit addresses (e.g., 192.168.1.1)
- • IPv6: 128-bit addresses (e.g., 2001:db8::1)
- • Private ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
Common Ports
- • HTTP: 80 | HTTPS: 443
- • DNS: 53 | SMTP: 25
- • SSH: 22 | FTP: 21
Subnet Masks
- • /24 = 255.255.255.0 (254 hosts)
- • /16 = 255.255.0.0 (65,534 hosts)
- • /8 = 255.0.0.0 (16,777,214 hosts)
DNS Records
- • A: IPv4 address mapping
- • AAAA: IPv6 address mapping
- • CNAME: Canonical name alias
- • MX: Mail exchange servers