ICMP Check / Ping Reboot (Avoid remote site engineer call-outs)
Cell Interface Ping (also referred to as ICMP Check, Ping Reboot, or Watchdog) is an automated connectivity monitor that restarts the router's cellular module when internet connectivity is lost. This feature is essential for unattended remote deployments where a physical site visit to power-cycle the router is costly or impractical.
Recommended: Enable Cell Interface Ping on all remote and unmanned router installations to minimise engineer call-outs and maximise uptime.
Why use Cell Interface Ping?
Mobile networks occasionally drop device sessions due to tower handovers, signal loss, IP lease expiration, or carrier-side timeouts. In most cases the connection recovers automatically. However, there are scenarios where the cellular module requires a restart to re-establish the connection — without this feature enabled, that means a site visit.
| State | Outcome |
|---|---|
| Without Cell Interface Ping | Router loses connectivity → remains offline indefinitely → requires engineer call-out |
| With Cell Interface Ping enabled | Router loses connectivity → failure detected → cellular module restarted → connectivity restored |
How it works
- The router sends ICMP ping requests to up to two configured host addresses at a regular interval
- If both hosts become unreachable after a configured number of consecutive retries, the router treats the cellular connection as failed
- The router performs the configured action — by default, restarting the cellular module
- After restarting, the router re-establishes its mobile network connection
Configuring two hosts (Host1 and Host2) reduces false positives — a restart is only triggered if both targets are unreachable. Use reliable, always-available hosts such as www.google.com or 8.8.8.8.
Configuration
Location in WebUI: Services > Cell Interface Ping
- Log in to the WebUI at
http://192.168.8.1 - Navigate to Services > Cell Interface Ping
- Tick Enable
- Review and adjust settings as required (see reference table below)
- Click Save and Apply
| Cell Interface Ping | |
| Enable | ✓ |
| Host1 to ping | www.google.com ipv4 or hostname |
| Host2 to ping | 8.8.8.8 |
| Ping packet size | 1 bytes (range 1–1000) |
| IPV6 | |
| Ping timeout | 4 seconds (range 1–10) |
| Max retries | 10 (range 3–1000) |
| Interval between ping | 2 minutes (range 1–1440) |
| Reconnect | |
| Start ping after cell up | ✓ |
| APN Reset | ✓ |
| Action when failed | Restart module ▼ |
| Save and Apply | |
Configuration reference
| Setting | Default | Notes |
|---|---|---|
| Enable | Unticked | Must be ticked to activate the service |
| Host1 to ping | www.google.com |
Primary ping target — hostname or IPv4 address. Use a reliable, always-available host. |
| Host2 to ping | 8.8.8.8 |
Secondary ping target. A restart is only triggered if both hosts are unreachable, preventing false positives from a single host being temporarily down. |
| Ping packet size | 1 byte | Size of each ICMP packet. The default 1-byte packet is sufficient for connectivity verification. |
| IPV6 | Unticked | Enable if pinging IPv6 hosts on an IPv6-capable network |
| Ping timeout | 4 seconds | Time to wait for a response before counting an attempt as failed (range: 1–10 seconds) |
| Max retries | 10 | Number of consecutive failed ping attempts (across both hosts) before the action is triggered. At the default 2-minute interval, this gives a 20-minute detection window before any restart occurs. |
| Interval between ping | 2 minutes | Time between each ping cycle (range: 1–1440 minutes) |
| Reconnect | Unticked | Attempts to reconnect the cellular interface before taking the action when failed. Enable if the carrier session drops frequently without requiring a full module restart. |
| Start ping after cell up | Ticked | Delays ping checks until the cellular interface has first come up after a reboot. Prevents false triggers during initial boot. |
| APN Reset | Ticked | Resets the APN configuration as part of the recovery sequence before restarting the module. Useful if carrier configuration drift is suspected. |
| Action when failed | Restart module | Action taken when the failure threshold is reached. Restart module restarts only the cellular modem — faster than a full reboot and sufficient in most cases. Other options may include a full device reboot depending on firmware version. |
Monitoring
Cell Interface Ping events are recorded in the system log. Navigate to Status > System Log and filter for ping or cell to view check activity. Log entries include successful responses, consecutive failures, and restart triggers with timestamps.
Frequent restart entries in the log indicate a persistent connectivity problem — this warrants investigation of signal strength, SIM status, or APN configuration rather than simply relying on auto-restart.
Best practices
| Recommendation | Detail |
|---|---|
| Enable on all remote deployments | Any router that cannot be easily power-cycled on-site should have Cell Interface Ping active |
| Use both host fields | Configure both Host1 and Host2 to prevent restarts caused by a single unreachable server — both must fail before action is taken |
| Use reliable targets | Google (www.google.com, 8.8.8.8) or Cloudflare (1.1.1.1) are appropriate defaults. For isolated networks, use your own always-on infrastructure. |
| Investigate frequent restarts | Regular module restarts are a symptom of an underlying network issue — check signal levels, SIM status, and APN settings rather than accepting the restarts as normal behaviour |
| Combine with scheduled reboot | A scheduled weekly reboot during a quiet maintenance window provides an additional reliability layer for long-running deployments |
| Test before deployment | Verify the feature is working by temporarily blocking outbound traffic and confirming the module restart occurs as expected |
Troubleshooting
| Issue | Resolution |
|---|---|
| Module restarts too frequently | Increase Max retries or the Interval between ping to reduce sensitivity. Also investigate whether there is a genuine connectivity problem. |
| Module does not restart despite lost connectivity | Verify Cell Interface Ping is enabled and saved. Confirm both ping hosts are reachable from the router under normal conditions. |
| Ping hosts unreachable even when internet is working | Some mobile operators or network policies block ICMP. Switch to different targets — try both a hostname and a numeric IP to rule out DNS issues. |
| False positives during high-traffic periods | Increase Max retries to reduce the chance of a transient high-latency period triggering a restart. |