FAQ

Basic Troubleshooting on Ethernet Networks

Network troubleshooting is a repeatable process to identify, test, and resolve issues on a network. Below is a quick FAQ-style guide to the most common tools and the basic steps you can follow.

Common Network Troubleshooting Tools

  • Switch Logs
    Record topology changes, link loss, PoE failures, errors and reboots. On EtherWAN switches, logs are available via both CLI and GUI.
    Switch system log showing topology change and PoE failure
    System log view (topology change / PoE events)
  • Ping
    Verifies IP reachability and measures round-trip time. Good quick check for IP routing, Layer-2 path, and basic cabling.
    • Tells you: routing/L2 path is up, fiber/cable likely OK
    • Doesn’t tell you: web/SSH/Telnet availability or VLAN correctness
    Ping output example verifying host reachability
    Ping results (latency / reachability)
  • Traceroute (Windows: tracert)
    Maps the routed path hop-by-hop and latency to each gateway; helps verify inter-VLAN routing and gateway health. Note: L2-only switches won’t appear.
    Traceroute hop-by-hop path and latency to destination
    Traceroute path and per-hop time
  • DDM (Digital Diagnostic Monitoring)
    From SFP/optical modules: mode, wavelength, length, temperature, TX/RX power; raises alarms for over-temp, LOS, laser faults (EtherWAN: web GUI).
    DDM optical link diagnostics showing temperature and TX/RX power
    Optical link health (DDM)
  • eVue (EtherWAN Network Monitoring)
    Discovers EtherWAN devices, visualizes topology, and notifies by email/SMS by severity. Centralizes multi-device monitoring across LAN/WAN.
    eVue topology view with device status and events
    eVue topology and events

Pro Tip

Start simple: Ping → Traceroute → Logs → DDM. Correlate with recent changes. For ongoing visibility, onboard devices into eVue to keep topology and events up to date.

Basic Troubleshooting Steps

  1. Identify the Problem — Ask users, capture symptoms, and note what changed just before the issue.
  2. List Probable Causes — Power, environment, subnets, servers, security; order from most to least likely.
  3. Test the Causes — Use Ping/Traceroute/Logs/DDM to confirm or eliminate each hypothesis.
  4. Create a Plan — Apply the fix; for complex cases, write out the steps and rollback.
  5. Verify & Prevent — Confirm service is restored; add guards (alerts, config checks) to avoid repeats.
  6. Document — Record findings, actions, and outcomes for future reference.

A structured approach is faster than guesswork. Combine these tools with a clear process, and consider eVue for continuous monitoring and faster mean-time-to-repair.