Articles
In-depth articles on CIDR notation, subnetting, private IP ranges, AWS VPC design, cloud networking, and network engineering — published regularly as new topics come up.
Looking for quick reference material? The Guides section has concise how-to pages on specific topics. These articles go deeper — more context, more background, more real-world application.
NAT Explained: How One Public IP Serves an Entire Office
Network Address Translation allows thousands of devices to share a single public IP address. Understanding how NAT works explains everything from home router behaviour to enterprise outbound firewalls.
The 127.0.0.0/8 Loopback Range: More Than Just localhost
Most engineers know 127.0.0.1 as localhost. But the entire 127.0.0.0/8 range — 16 million addresses — is reserved for loopback. Here's what that means and when the other addresses matter.
Subnetting for Beginners: From /24 to /28 in 10 Minutes
Subnetting divides a larger network into smaller, more manageable segments. This step-by-step tutorial walks through the maths using a /24 as the starting point.
How to Check If an IP Address Falls Within a CIDR Block
Determining whether a given IP address belongs to a specific CIDR range is a common task in security analysis, routing, and access control. Here are multiple approaches — manual math, tools, and code.
Azure IP Ranges and Service Tags: What Network Engineers Need to Know
Azure organises its IP ranges into Service Tags — named groups covering specific services and regions. Understanding how to use them simplifies firewall rules and is essential for hybrid connectivity.
CIDR Aggregation and Route Summarization Explained
Route summarization collapses multiple specific prefixes into one larger advertisement. It reduces routing table size, speeds convergence, and hides network topology from upstream routers.
Kubernetes Pod CIDR: Planning Your Cluster Address Space
Kubernetes requires three non-overlapping CIDR blocks: one for nodes, one for pods, and one for services. Choosing these correctly at cluster creation time prevents painful re-addressing later.
Wildcard Masks vs CIDR Notation: Understanding the Difference
Cisco ACLs use wildcard masks instead of subnet masks. A wildcard mask is the bitwise inverse of a subnet mask — 0 bits match, 1 bits are ignored. Here's how to convert between the two.
The /30 Subnet: Point-to-Point Links Between Routers Explained
A /30 subnet provides exactly 4 IP addresses — 2 usable hosts plus a network and broadcast address. It is the traditional choice for WAN point-to-point links between two routers.
VPC CIDR Best Practices for Multi-Region AWS Deployments
Choosing VPC CIDR blocks is easy to get wrong — and hard to fix later. Multi-region deployments need non-overlapping address spaces that support VPC peering, Transit Gateway, and on-premises connectivity.
How to Calculate Usable Hosts in Any CIDR Block
The formula for usable hosts in a CIDR block is straightforward — but there are edge cases for /31 and /32 that break the pattern. Here's the complete calculation with worked examples.
Classful vs Classless: The History That Changed IP Addressing Forever
Before CIDR, every IP address belonged to a fixed Class A, B, or C network. The shift to classless routing in 1993 saved the internet from running out of address space years earlier than it did.