CyberSecurity & DevSecOps Expert: Develop, PenTest, and Deploy Secure Applications

CIDR subnets and notation

Understanding how IP addresses are organized and divided is a fundamental skill for anyone working in cybersecurity or network administration. You have already explored ports, transport protocols, and packet capture with tools like Wireshark and Nmap...

Filter UDP DNS traffic

**Theoretical Recap** DNS (Domain Name System) is the protocol responsible for translating human-readable domain names (e.g., google.com) into IP addresses that machines can route. By default, DNS operates over UDP on port 53 — a deliberate design ch...

Common Wireshark Filters (BPF)

When you open Wireshark and start a capture on a busy network interface, you are immediately flooded with hundreds or even thousands of packets per second. Without a way to narrow down what you see, finding the traffic you care about becomes nearly i...

Capturing a TCP handshake with Wireshark

**Theoretical Recap** The TCP three-way handshake is the mechanism by which two hosts establish a reliable connection before any data is exchanged. It consists of three segments: SYN (client initiates, proposes an Initial Sequence Number), SYN-ACK (s...

Introduction to Wireshark: Interface and Workflow

Wireshark is one of the most widely used network protocol analyzers in the world. It allows you to capture and interactively browse the traffic running on a computer network. In the context of cybersecurity and DevSecOps, Wireshark is an essential to...