Detect when a WAN is down (does not have internet access) to launch a script?

[dwr953topfsense]

Hello

I want to know how I can detect when a WAN is down (down meaning it has no internet access thru that interface) and then if detected, launch a personal script.

Thanks

[Mr_AJ]

You something like this

https://forum.netgate.com/topic/124545/monitoring-pfsense-using-nagios-and-ssh

Or a bash script like this .....

if curl -s --head  --request GET https://example.com | grep "200 OK" > /dev/null; then 
   echo "mysite.com is UP"
else
   echo "mysite.com is DOWN"
fi