🔍 Step 1: Define the Pattern
Before you can diagnose intermittent drops, you need data. The most useful information:
| Question | Why It Matters | How to Find Out |
|---|---|---|
| How long does each dropout last? | <30s = router; 30s–5min = line; >5min = ISP | Note times when it happens |
| What time does it happen? | Daytime = congestion; anytime = hardware/line | Keep a log for 1 week |
| Does it affect all devices or one? | One device = local problem; all = router/line | Test multiple devices simultaneously |
| Does it happen at the router or just WiFi? | Router = serious; WiFi only = local issue | Test via ethernet cable |
| Does the router reconnect on its own? | Auto = ISP DHCP renewal; manual = hardware fault | Check router admin logs |
📋 Step 2: Check Router Logs
Every business router keeps logs. Log into your router admin page (typically 192.168.1.1 or 192.168.0.1) and look for the event log or WAN connection log. Look for: PPPoE disconnection events, DHCP renewal failures, hardware fault codes. These timestamps will tell you exactly when disconnections occurred and often indicate the cause.
⚙️ Step 3: The Most Common Causes by Connection Type
| Connection | Most Common Dropout Cause | Diagnostic |
|---|---|---|
| FTTC (fibre-to-cabinet) | Copper section between cabinet and premises | BT Wholesale line checker — check SNR margin |
| FTTP (full fibre) | ONT fault or router PPPoE issue | Check ONT PON light; try router reboot |
| Leased line | Carrier network issue or physical fault | ISP fault portal; check WAN port status |
| 4G/5G router | Signal fluctuation or cell congestion | Signal strength display in router admin |
| Any connection | Router overheating or memory leak | Touch router — hot? Force restart; check uptime |
📡 Step 4: FTTC Specifically — SNR Margin
FTTC connections (copper from the cabinet to your building) degrade over time and with weather. The key diagnostic metric is SNR margin (Signal-to-Noise Ratio). You can check this in your router's DSL statistics page. A healthy FTTC line has SNR above 6dB; below 3dB and dropouts become frequent. If your SNR is marginal, a BT engineer visit (typically free if there's a proven line fault) is needed.
☎️ Step 5: When It's the ISP's Network
Some intermittent issues originate in the ISP's core network rather than your line or equipment — routing instability, BGP issues, DDoS affecting shared infrastructure. These are harder to diagnose locally. Signs it's the ISP: multiple customers in your area reporting the same issue simultaneously (check DownDetector), the issue resolves spontaneously without any local changes, and the router logs show a clean connection that nonetheless can't reach internet addresses.
🛡️ The Permanent Solution: Failover
The most reliable fix for intermittent broadband outages is failover — a second internet connection that activates automatically when the main line drops. Telexico's Assure-X failover controller monitors your primary connection and switches to 4G/5G within 30 seconds of a dropout, without any manual intervention.
- FTTP primary + 4G failover: around £50–75/month extra — the most common SME setup.
- Leased line + FTTP failover: typical enterprise dual-WAN configuration.
- Primary + Starlink failover: for rural sites where 4G coverage is poor.
Add automatic failover to your existing broadband — Telexico's Assure-X activates within 30 seconds of a dropout.
Add Failover Protection →