– Draw arrows between routers and label next hops.
| Mistake | Consequence | Fix | |---------|-------------|-----| | Using /32 on a LAN | Only one host possible – other devices can’t talk | Use /24 or /16 for LANs | | Wrong gateway on client | Traffic leaves client but cannot come back | Set gateway to router’s IP on same subnet | | Missing return route | Ping works one way only | Always check route back to source | | Overlapping networks | Two interfaces on same wire with different netmasks | Recalculate CIDR; use unique network IDs | | Assigning network/broadcast IP | Interface refuses it | Use host range (e.g., .1 to .254 ) | netpractice 42 tutorial
| Mistake | Fix | |---------|-----| | Wrong netmask | Use /24 for small LAN, /30 for point-to-point links | | Missing gateway | Hosts need gateway to leave their subnet | | Incorrect next hop | Must be an IP on the same link as the source interface | | Overlapping subnets | Each subnet must be unique, non-overlapping | | Host IP = network/broadcast | First IP is network, last is broadcast – don’t assign | – Draw arrows between routers and label next hops
is a fundamental networking project in the 42 school curriculum designed to teach students the mechanics of TCP/IP addressing, subnetting, and routing . Unlike coding projects, this exercise uses an interactive trainer where you must configure 10 increasingly complex network scenarios to ensure all devices can communicate. Core Networking Concepts to Master Core Networking Concepts to Master