Ravindra BagaleCourses & study guides

Chapter 1: Networking Fundamentals

Practice Questions and Lab Exercises

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  1. Differentiate between an IP address and a port with a real-life analogy.
  2. List the default ports for SSH, HTTP, HTTPS, MySQL, MongoDB and a Flask development server.
  3. Identify the class and default mask of: 10.4.5.6, 172.20.1.1, 200.1.2.3, 230.0.0.5.
  4. A network 172.16.0.0/22 must be split into 8 equal subnets. Find the new prefix, block size and the range of the 3rd subnet.
  5. Shorten 2406:da1a:0000:0000:0e00:0000:0000:0010 correctly. Why can :: be used only once?
  6. Which of these are private: 10.10.10.10, 172.32.1.1, 192.168.100.1, 100.64.1.1, 8.8.8.8?
  7. Lab: On any Linux machine run ip addr, hostname -I and curl -s https://checkip.amazonaws.com. Explain why the two IPs differ (hint: NAT).
  8. Explain the difference between an auto-assigned public IP and an Elastic IP on AWS. What happens to each when you stop the instance?

Quick Revision

  • IP = which host; port = which service. Socket = IP:port.
  • Must-know ports: 22 SSH, 80 HTTP, 443 HTTPS, 3306 MySQL, 27017 MongoDB, 3000 Node, 5000 Flask, 8080 alt-HTTP.
  • IPv4 = 32 bits, 4 octets; classes A/B/C/D/E; CIDR /n → 2^(32−n) addresses; AWS reserves 5 per subnet.
  • IPv6 = 128 bits, 8 hex groups; drop leading zeros; :: only once.
  • Private (RFC 1918): 10/8, 172.16/12, 192.168/16. Default VPC = 172.31.0.0/16.
  • NAT lets private hosts share a public IP. AWS: IGW (1:1), NAT Gateway (many:1).
  • Auto public IP changes on stop/start; Elastic IP is static.