Stage 2 · Lesson 1 of 8
IP addresses, subnets and CIDR
Every machine on a network has an , a number such as 10.0.1.25 that other machines use to reach it. A subnet is a range of neighbouring addresses. It is written in CIDR notation, such as 10.0.1.0/24.
The /24 means the first 24 of the 32 bits name the network. That leaves 8 bits, or 256 addresses, for machines; a /16 holds 65,536. Some ranges are private: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.
The internet cannot reach them directly. So servers in them need or a to be reached, or to reach out. You need this the first time you design a , pick subnets that do not overlap or write rules.
Common trapchoosing ranges that overlap with an office network or another VPC you will later need to connect to.
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Resources for this stage
Start with
- VideoFreeComputer Networking: A Top-Down Approach (Video Lectures)
Jim Kurose and Keith Ross · Intermediate
Free lectures from the textbook authors; chapters 1 to 4 cover what DevOps needs
Practise
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