Subnet masks define which part of an IP address represents the network and which represents individual hosts.
CIDR notation
- /24 = 255.255.255.0 (256 addresses, 254 usable).
- /16 = 255.255.0.0 (65,536 addresses).
- /8 = 255.0.0.0 (16,777,216 addresses).
Subnetting benefits
- Efficient IP address allocation.
- Network segmentation for security and performance.
- Isolation of broadcast domains.
- Simplified routing and management.
Calculations
- Network address: IP AND subnet mask.
- Broadcast address: Last IP in the range.
- Usable hosts: Total addresses - 2 (network + broadcast).
Related Articles
View all articles
Threat Modeling with STRIDE and DREAD: A Complete Guide to Proactive Security Architecture
Master threat modeling with STRIDE and DREAD frameworks to identify, classify, and prioritize security threats before they become vulnerabilities. This comprehensive guide covers data flow diagrams, mitigation mappings, MITRE ATT&CK integration, and building an enterprise threat modeling program.
Read article →
AWS S3 Security Best Practices: Encryption, Access Control & Compliance
Secure your AWS S3 buckets with this comprehensive guide covering encryption options, IAM and bucket policies, Block Public Access, VPC endpoints, and compliance configurations.
Read article →
Cloud Penetration Testing: A Complete Guide for AWS, Azure, and GCP
Cloud penetration testing requires different approaches than traditional network testing. Learn cloud provider policies, testing methodologies, and common findings across AWS, Azure, and GCP environments.
Read article →
AWS Fargate Explained: Serverless Containers Without Managing Servers
Learn what AWS Fargate is, how it compares to EC2 for containers, pricing considerations, and when to use Fargate vs ECS on EC2. Complete guide for decision-makers.
Read article →Explore More Networking
View all termsBGP (Border Gateway Protocol)
The routing protocol that exchanges network reachability information between autonomous systems, forming the backbone of Internet routing.
Read more →DNSSEC (DNS Security Extensions)
A suite of specifications that add cryptographic authentication to DNS responses, preventing DNS spoofing and cache poisoning attacks.
Read more →Domain Name System (DNS)
The hierarchical naming system that translates human-readable domain names into IP addresses.
Read more →IP Address Geolocation
The process of determining the geographic location of an internet-connected device using its IP address.
Read more →MAC Address
A unique hardware identifier assigned to network interfaces for local network communication.
Read more →MX Record
A DNS record type that specifies which mail servers are responsible for receiving email for a domain.
Read more →