A router must know where to send packets for a destination network (next-hop IP).
| Error | Why? | Fix | |-------|------|-----| | Ping fails on same switch | Different subnet masks | Unify mask | | Host can’t reach gateway | Gateway IP outside host subnet | Move gateway inside host subnet | | Router can’t ping far network | Missing route back | Add return route | | IP collision | Two devices same IP | Change one | | Wrong broadcast usage | Assigning .255 as host IP | Use .254 or lower for hosts | netpractice 42 tutorial
This means: "If you don't know where to send the packet, send it here." A router must know where to send packets
The project progresses through 10 distinct exercises in a web-based simulator: netpractice 42 tutorial
Two routers connected directly – only 2 usable IPs.