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Local Server Hosting and Network Organization

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Local Server Hosting

Using Python (Simple HTTP Server)

To quickly host a local server, you can use Python’s built-in HTTP server module.

Steps

  1. Open Terminal.

  2. Navigate to the directory you want to serve:

    cd /path/to/your/directory

  3. Start the server:

  • For Python 3.x:
python3 -m http.server 8000
  1. Access the server: Open a browser and navigate to http://<your-local-ip>:8000.

SSH into Your Local Server

Ensure SSH Server is Running

  1. Check if SSH is enabled
sudo systemsetup -getremotelogin
  1. Enable if it is off
sudo systemsetup -setremotelogin on
  1. Get your local ip adress(its usually en0
ifconfig
  1. SSH into the machine
ssh <username>@<your-local-ip>

Network Structure/Organization

Basics of Networking

  • IP Addresses: Unique identifiers for devices on a network.
    • IPv4: 192.168.1.1
    • IPv6: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
  • Subnets and Subnet Masks: Subdividing a network.
    • Example Subnet Mask: 255.255.255.0
  • DNS (Domain Name System): Translates domain names to IP addresses.

Common Networking Protocols

  • HTTP/HTTPS: Web communication protocols. HTTPS is secure.
  • TCP/IP: Fundamental protocol suite for the internet.
  • UDP: Connectionless protocol for speed over reliability.
  • SSH (Secure Shell): Securely access remote machines.

Tools and Commands

HTTP Requests

  • cURL: Command-line tool for transferring data with URLs.
curl http://example.com
curl -X POST http://example.com -d "param1=value1&param2=value2"

Network Information

  • ifconfig/ip: Displays network configuratio
ifconfig
ip addr show
  • ping: Tests connectivity between devices.
ping 8.8.8.8
  • traceroute: Traces the path packets take to a destination.
traceroute example.com
  • netstat: Displays network connections, routing tables, interface statistics.
netstat -a

SSH

  • SSH Commands: Connecting, copying files, running remote commands
ssh user@host
scp file user@host:/path/to/destination
ssh user@host 'command'

Network Analysis

  • Wireshark: GUI tool for network protocol analysis.
  • tcpdump: Command-line packet analyzer.
sudo tcpdump -i eth0

Network Organization

Local Network Structure

  • Router: Central device that connects devices within a local network.
  • Switch: Device to expand the number of devices on a network.
  • Subnetting: Dividing a network into smaller sub-networks.

Internet Network Structure

  • ISP (Internet Service Provider): Provides internet access.
  • Backbone: High-capacity data transmission lines that carry internet traffic.
  • DNS Servers: Translate domain names to IP addresses.
  • CDNs (Content Delivery Networks): Distribute content to reduce latency.

Advanced Topics

HTTP/2 and HTTP/3

  • HTTP/2: Multiplexing, header compression, efficient use of resources.
  • HTTP/3: Based on QUIC, reduced latency, improved security.

Firewalls and Security

  • iptables/nftables: Tools for configuring Linux kernel firewall
sudo iptables -L
sudo nft list ruleset
  • SSL/TLS: Secure communication protocols.

Programming and Network Code

  • Python: Libraries like requests for HTTP, socket for low-level operations.
import requests
response = requests.get('http://example.com')
 
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('example.com', 80))
s.sendall(b'GET / HTTP/1.1\r\nHost: example.com\r\n\r\n')
response = s.recv(4096)
print(response)

Resources

  • Books:
    • “TCP/IP Illustrated” by W. Richard Stevens.
    • “Networking for Systems Administrators” by Michael W. Lucas.
  • Online Courses:
    • Networking courses on Coursera and edX.
    • Tutorials on Codecademy and Udemy.
  • Documentation:
    • Official docs for tools like cURL, Wireshark, tcpdump.
    • RFC documents for detailed protocol specifications.