Capturing a TCP handshake with Wireshark

Adjust the subnetwork for a need

**Theoretical Recap** A subnet (subnetwork) is a logical subdivision of an IP network. The core tool for defining subnets is CIDR (Classless Inter-Domain Routing) notation, written as an IP address followed by a prefix length (e.g., 192.168.1.0/24). ...

Calculate the /24 and /26 address range

**Theoretical Recap** An IP address in IPv4 is a 32-bit number divided into two parts: the network portion and the host portion. CIDR notation (Classless Inter-Domain Routing) expresses this split using a suffix like /24 or /26, which indicates how m...

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...