Stage 1 · Lesson 3 of 7
IP addresses, CIDR and subnets
An address is 32 bits, written as four numbers such as 10.0.1.25. CIDR notation, like 10.0.0.0/16, says how many leading bits are fixed: the smaller the number after the slash, the bigger the block. A /16 holds 65,536 addresses and a /24 holds 256.
Three ranges are private and never routed on the internet: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. Every cloud network and you create asks for a CIDR block, and each cloud keeps a few addresses in every subnet for itself.
Common trapgiving every network the same range, such as 10.0.0.0/16, so that two of them can never be connected later.
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
- CourseFreeLinux Upskill Challenge
Linux Upskill Challenge · Beginner
Free, one task a day on a real cloud server: the shell skills this roadmap assumes
- VideoFreeComputer Networking: A Top-Down Approach (Video Lectures)
Jim Kurose and Keith Ross · Intermediate
Free lectures: watch the chapters on the application, transport and network layers for IP, TCP, UDP and DNS