"Router R1 is connected to Router R2. R2 is connected to R3 and R4. Use OSPF to route traffic from R1 to R4."
| 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 | netpractice 42 tutorial
| CIDR | Mask (Last Octet) | Block Size (Magic Number) | Subnets | | :--- | :--- | :--- | :--- | | /25 | 128 | 128 | 0 - 127, 128 - 255 | | /26 | 192 | 64 | 0 - 63, 64 - 127, 128 - 191, 192 - 255 | | /27 | 224 | 32 | 0 - 31, 32 - 63, etc... | | /28 | 240 | 16 | 0 - 15, 16 - 31, etc... | "Router R1 is connected to Router R2