How to Diagnose Intermittent Network Failures with Packet Capture

At 2:13 a.m., the NOC dashboard still looked healthy. CPU on the core switches was normal. Interface utilization was below 40%. SNMP polling showed no down links. The application team insisted their new deployment was fine. Yet users in two branch offices kept reporting the same maddening symptom: the ERP web app would load, spin for 20 to 40 seconds, and then fail with a timeout. Five minutes later, it might work again. This is the kind of incident that turns routine network troubleshooting int