NetPractice is an introductory project to the world of networking. Through 10 progressive exercises, you'll learn fundamental concepts of TCP/IP addressing by configuring small-scale networks to enable communication between devices.
- IP addressing and subnetting
- Network configuration
- Routing table management
- Network troubleshooting
- Understanding network topologies
A computer network is a collection of interconnected devices that communicate by sending and receiving data packets.
🌍 Public Networks (Internet)
- Global connectivity
- Managed by ISPs
- Minimal access control
- Examples: Internet, public Wi-Fi
🏠 Private Networks
- Restricted access
- Local connectivity
- Enhanced security
- Examples: Home networks, corporate LANs
The TCP/IP model consists of four layers working together to ensure reliable data transmission:
| Layer | Protocols | Function |
|---|---|---|
| Application | HTTP, FTP, SMTP | User services and interfaces |
| Transport | TCP, UDP | Reliable data delivery |
| Internet | IP, ICMP | Routing and addressing |
| Network Access | Ethernet, Wi-Fi | Physical data transmission |
🔗 TCP (Transmission Control Protocol)
- Breaks data into packets
- Ensures reliable delivery
- Reassembles data at destination
📍 IP (Internet Protocol)
- Provides unique addressing
- Routes data across networks
- Two versions: IPv4 and IPv6
An IPv4 address is a 32-bit number divided into four 8-bit octets:
192.168.1.100
│ │ │ │
└───┴──┴──┴── Each octet: 0-255 (8 bits)
Understanding binary is crucial for subnetting:
IP Address: 192.168.1.100
Binary: 11000000.10101000.00000001.01100100
Every IP address consists of:
- Network portion: Identifies the network
- Host portion: Identifies the device
A subnet mask determines which bits represent the network vs host:
IP Address: 192.168.1.100
Subnet Mask: 255.255.255.0 (/24)
Network: 192.168.1.0
Host: 0.0.0.100
CIDR (Classless Inter-Domain Routing) uses slash notation:
| CIDR | Subnet Mask | Available IPs | Usable IPs | Use Case |
|---|---|---|---|---|
| /30 | 255.255.255.252 | 4 | 2 | Point-to-point |
| /29 | 255.255.255.248 | 8 | 6 | Small office |
| /28 | 255.255.255.240 | 16 | 14 | Department |
| /27 | 255.255.255.224 | 32 | 30 | Floor network |
| /26 | 255.255.255.192 | 64 | 62 | Building network |
| /25 | 255.255.255.128 | 128 | 126 | Large department |
| /24 | 255.255.255.0 | 256 | 254 | Standard LAN |
These ranges are reserved for private networks:
| Range | Class | CIDR | Usage |
|---|---|---|---|
| 10.0.0.0 - 10.255.255.255 | A | /8 | Large organizations |
| 172.16.0.0 - 172.31.255.255 | B | /12 | Medium networks |
| 192.168.0.0 - 192.168.255.255 | C | /16 | Small networks/homes |
| 127.0.0.0 - 127.255.255.255 | - | /8 | Loopback testing |
A switch connects devices within the same network (LAN):
Characteristics:
- Operates at Layer 2 (Data Link)
- No IP configuration required
- Forwards traffic based on MAC addresses
- Cannot communicate between different networks
A router connects multiple networks together:
Characteristics:
- Operates at Layer 3 (Network)
- Has IP interface for each connected network
- Routes traffic between different networks
- Maintains routing tables
Important: Router interfaces cannot have overlapping IP ranges!
Below are all NetPractice levels with their topologies and a short note for each. Click each section to expand and view the image and summary.
Level 1: Basic Host Communication
Goal: Make two pairs of hosts communicate directly.
Key: Both hosts in each pair must share the same network and subnet mask.
Level 2: Subnetting Practice
Goal: Assign IPs with different subnet masks, ensuring all hosts in a network use the same mask and valid IP range.
Level 3: Switch Network
Goal: All clients are connected through a switch.
Key: Every client must have an IP in the same network.
Level 4: Router Interfaces
Goal: Assign IPs to routers and hosts without overlapping subnets for each router interface.
Level 5: Routing Tables
Goal: Configure routing tables so clients in different networks can reach each other.
Level 6: Internet Access
Goal: Connect a local client to the Internet via a router using default routes.
Level 7: Multi-Router Topology
Goal: Configure multiple routers and subnets, planning address ranges to avoid overlap.
Level 8: Limited Address Space
Goal: Provide Internet to multiple hosts within a constrained public range.
Level 9: Advanced Integration
Goal: Combine subnetting, routing, and multi-network integration in a complex topology.
Level 10: Final Challenge
Goal: Build a complete, efficient network with correct allocation, routing, and no waste.
# IP Configuration
ip addr show # Show IP addresses
ifconfig # Legacy IP configuration
# Connectivity Testing
ping 192.168.1.1 # Test connectivity
traceroute 8.8.8.8 # Trace network path
# Routing
ip route show # Display routing table
route -n # Legacy routing table
# Network Analysis
netstat -rn # Network statistics
ss -tuln # Socket statistics- "Computer Networking: A Top-Down Approach" by Kurose & Ross
- "TCP/IP Illustrated, Volume 1" by W. Richard Stevens
- "Network+ Guide to Networks" by Tamara Dean
- Wireshark - Network protocol analyzer
- GNS3 - Network simulation platform
- Packet Tracer - Cisco network simulator
"In networks, we trust the protocol."
⭐ If this helped you, please give it a star! ⭐