That’s it. Every puzzle reduces to this rule.
Complete 10 levels (from basic to incredibly complex) with 100% success. netpractice 42 tutorial
| Mistake | Fix | |---------|-----| | Using same IP twice | Each interface must have unique IP | | Wrong mask on one side of link | Both ends must agree on network address | | Forgetting gateway on hosts | Hosts need default gateway for off-LAN traffic | | Routing through wrong next hop | Next hop must be directly reachable | | Misplacing router’s own interface IP | Router’s IP in a LAN is the gateway for that LAN | That’s it
If Interface A and Interface B are on the same switch, their IP addresses must start with the same network bits. | Mistake | Fix | |---------|-----| | Using
Example: If the mask is /24 , the first three numbers (octets) must be identical.
If two devices are connected via a switch, they must have the . If they don't, they cannot understand each other's range.