Network Fundamentals for Pentesters

What you'll learn

• Explain how data actually moves across a network, from a single frame to a full TCP session
• Subnet an IPv4 network by hand and read CIDR notation without a calculator
• Describe how switches and routers make forwarding decisions, and why VLANs and segmentation exist
• Explain TCP's three-way handshake and UDP's statelessness, and why that difference matters for scanning later
• Trace how DNS resolution works end-to-end and identify DNS as an attack surface
• Identify the core services (HTTP/S, SMB, FTP, SSH, RDP, SNMP) running on a network and what each one is for
• Explain what a firewall actually filters and how NAT changes what's reachable from where
• Read a real packet capture in Wireshark and tcpdump and explain what happened

Who this course is for

Anyone starting a pentesting or offensive security path who doesn't already have solid networking fundamentals, including people who've tried to learn networking before and found it too abstract or too exam-focused. This is the prerequisite course for Network Penetration Testing on this platform; no prior networking certification or experience assumed, just basic comfort with a computer.