NetPractice requires you to calculate boundaries quickly. Use this binary scale for a single octet to convert masks instantly: Bit Position Common Subnet Mask Conversions /24 = 255.255.255.0 (Block size: 256) /25 = 255.255.255.128 (Block size: 128) /26 = 255.255.255.192 (Block size: 64) /27 = 255.255.255.224 (Block size: 32) /28 = 255.255.255.240 (Block size: 16) /29 = 255.255.255.248 (Block size: 8) /30 = 255.255.255.252 (Block size: 4) 3. Step-by-Step Problem Solving Framework
The computers in 192.168.1.0/24 must have their "default gateway" set to the IP of the router interface in that same network. Level 7–10: Complex Routing Tables
The Gateway IP on the computer must be the exact IP of the router side it connects to. Levels 7 to 10: Subnetting Puzzles
The logs at the bottom of the page are incredibly useful. They'll tell you precisely why your configuration is wrong—whether it's a mismatched subnet, an unreachable gateway, or a misrouted packet.
Let’s solve a common intermediate level. netpractice 42 tutorial
Before you start, memorize this formula. It is the key to solving every exercise:
R1 wants to reach 192.168.2.0/24 via R2: ⇒ Add route on R1: 192.168.2.0/24 via 10.0.0.2
An IPv4 address is a 32-bit number, typically written in —four octets (each 0-255) separated by dots: 192.168.1.1 . Every device needs a unique IP address to communicate on a network. Each address has two components:
Example: Router A ↔ Router B: A: 10.0.0.1/30 → B: 10.0.0.2/30 NetPractice requires you to calculate boundaries quickly
You need to memorize the "Magic Numbers" to calculate subnets fast.
: Remember that 10.0.0.0/8 , 172.16.0.0/12 , and 192.168.0.0/16 are standard private spaces.
First, read the "Goal" message at the top of the interface. It tells you exactly what needs to be accomplished (e.g., "Make Client A able to ping Server B " or "Allow Client A to access the Internet").
Example: 10.0.0.1/24 can talk to 10.0.0.2/24 . It cannot talk to 10.0.1.2/24 . Levels 4 to 6: Introducing Routers Level 7–10: Complex Routing Tables The Gateway IP
The very last address in the range (host bits are all 1). It is used to send data to all hosts on the subnet. Example: For the network 192.168.1.0/24 : Network Address: 192.168.1.0 First usable host: 192.168.1.1 Last usable host: 192.168.1.254 Broadcast Address: 192.168.1.255 4. Routing Tables and Default Gateways A routing table tells a device where to send data packets. Destination: The target network you want to reach.
A ping requires a two-way street. If Client A can send a packet to Client B, but Client B’s router doesn't know the route back to Client A's network, the simulation will fail. Always trace the packet forward and backward.
For a host to reach another network, its routing table must list the router’s local interface as the Next Hop . Levels 7–10: Advanced Routing & Public vs. Private IPs