Use Connection monitoring to be notified of potential upstream connectivity issues, so you can more easily or automatically ensure continued service.
How Connection monitoring works
When Connection monitoring is on:
- The interface checks the Internet connection by performing a DNS lookup for smoothwall.net to Google's public DNS servers (8.8.8.8 or 8.8.4.4) every 15 seconds, in a round-robin sequence with a 5-second delay between each lookup.
- If six consecutive lookups fail (after a total of 120 seconds), the Smoothwall Appliance considers the Gateway down and stops sending traffic to that interface.
Tip
You can set up Source NAT rules using a Link Load Balancing pool to automatically reroute traffic through a different Gateway when the usual Gateway is down.
- If another Gateway is available, and you have System Alerts turned on, the Smoothwall Appliance alerts you when the usual Gateway is down. If email alerts are on, the subject line is ‘Monitor Alert for <hostname>’.
- The interface continues to poll the DNS servers. When a lookup is successful, the Smoothwall Appliance considers the Gateway up and resumes sending traffic to that interface again. If you have System Alerts turned on, the Smoothwall Appliance sends you another alert.
Connection monitoring has no effect, and you won’t be sent alerts when either:
- You only have one Gateway because, when this Gateway is down, traffic can’t be routed to another interface.
- Your Smoothwall Appliance doesn’t manage internet access.
Turn Connection monitoring on or off
- Go to Network > Configuration > Interfaces.
- Find the interface, then select IP addresses. You’ll see an Attached addresses table.
- Hover over the interface and select Edit.
- Select the Connection monitoring Enabled checkbox to turn on the feature. Clear the checkbox to turn off Connection monitoring.
- Select Save changes.