Wired and wireless network problems: intermittent or no connectivity, APIPA address, IP conflicts, slow speeds, high latency and jitter, interference, SSID not found, port flapping

Network problems are among the most common help desk calls. A structured approach, starting at the physical layer and working upward, saves a lot of time: check cables, lights and wireless signal first, then IP configuration, then name resolution and services. Commands such as ipconfig, ping, tracert and nslookup help at each stage.