Stage 1 · Lesson 3 of 8
The networking you need
Most security work means reading what happens on a network, so the basics need to be solid. Every device has an , and a subnet is a group of nearby addresses. Programs talk through numbered doors called .
TCP checks that all the data arrives; UDP is quicker and does not check. DNS turns names like example.com into addresses. is how browsers ask for pages, and HTTPS is the same thing protected by TLS .
A firewall decides which traffic may pass, and a proxy passes traffic on for you. Learn what normal looks like. A browser looks up a name with DNS, connects over TCP to port 443 and then sets up TLS.
Once you know this path, odd traffic in a log or a stands out. You do not need to configure routers for a first role, but you must explain what happens when you type a web address.
Common trapmemorising port numbers without understanding the handshake and the protocols behind them.
A question to check yourself, an AI practice session and 2 cheat sheet entries come with the full roadmap. Unlock
Resources for this stage
Start with· follow one of these
- CourseFreeProfessor Messer's Security+ (SY0-701) Course
Professor Messer · Beginner
Free video course whose early sections cover general security concepts, threats and cryptography at exactly the right depth
- PlatformFreeTryHackMe
TryHackMe · Beginner
The free pre-security and introductory rooms teach networking, Linux and web basics in guided, browser-based labs