Systems & Networking

Goal
This module reveals how computers communicate across the internet. Understanding networking is essential for deploying AI models, debugging connection issues, and building secure, scalable systems.
Estimated Time Impact
4-6 hours total
Network Fundamentals(2.5h)
Models & Protocols(1.25h)
Security & Addressing(1.5h)
1. Network Fundamentals
Core Concepts: Switches & Routers
video
beginnerNetworkChuck: Networking Series (Videos 1 - 3)
What You'll Learn
- Network: Two or more connected devices sharing resources.
- Switch (Layer 2): Connects devices within a single network (LAN) using MAC addresses.
- Router (Layer 3): Connects different networks together (LAN to WAN) using IP addresses.
How to Use
- Watch the videos on Networks, Switches, and Routers.
- Practice: Run
ipconfig(Windows) orifconfig(Mac/Linux) to find your IP address and Default Gateway. - Trace: Run
traceroute google.comto see every router your data passes through.
2. Security & Addressing
Ports & Security
video
intermediatePort Security Essentials
Ports are logical "doors" on a server. Only open the ones you absolutely need.
Common Ports:
- 80/443: Web traffic (HTTP/HTTPS)
- 22: Remote access (SSH)
- 8000: FastAPI development server
- 5432: PostgreSQL database
Action Items:
- Check your open ports:
netstat -an. - Configure a firewall rule to allow port 8000 but block others.
IP Addressing & Subnetting
video
advancedIP Addressing & Subnetting
- IPv4: 32-bit address (e.g., 192.168.1.1).
- Subnetting: Dividing a network into smaller, secure segments.
- Private IPs: Ranges like
192.168.x.xor10.x.x.xare not accessible from the public internet.
Action Items:
- Practice CIDR notation (e.g.,
/24means 254 usable hosts). - Identify whether your current IP is Public or Private.
Practical Project: Secure AI Architecture
Task: Design a secure network architecture for a production AI system.
Requirements:
- Public Subnet: Contains a Load Balancer (Ports 80/443 open to world).
- Private Subnet (App): Contains FastAPI Servers (Port 8000, accepts traffic only from Load Balancer).
- Private Subnet (Data): Contains Database (Port 5432, accepts traffic only from App Subnet).
Deliverable: A diagram showing the traffic flow and security rules.
Note: For hands-on implementation of deploying AI services with Docker and cloud security, see the Infra Basics module.
Checklist & Troubleshooting
Verify You Can:
- Explain the difference between a Switch and a Router.
- List the 4 layers of the TCP/IP model.
- Identify Private vs Public IP addresses.
- Debug connection issues using
pingandtelnet.
Common Pitfalls:
- Connection Refused: The service isn't running, or the port is closed.
- Timeout: A firewall is blocking the connection, or there is a routing issue.
- Works Locally, Not in Prod: You might be listening on
127.0.0.1(localhost) instead of0.0.0.0(all interfaces).
Quick Reference
# Diagnostics
ping google.com # Check connectivity
traceroute google.com # Trace the path to a server
netstat -tuln # List listening ports (Linux)
ip addr # Show IP addresses
# Common Ports
22: SSH | 80: HTTP | 443: HTTPS
5432: Postgres | 8000: FastAPI