Some firewalls (CSF for instance) have a limit of maximum overall PING requests per second that your server can receive.
The default limit is set to 1/s, meaning one request per second, so if more than 1 of our monitors all ping your server at the same time, then some/most of them will fail due to this limit.
If you select PING monitoring type, then please remove or increase this limit in your CSF to avoid false alarms.
Here’s how you can raise or remove the PING per second limit in your CSF firewall:
Open the CSF configuration file:
nano /etc/csf/csf.conf
Find ICMP_IN_RATE
Either set it higher than 1/s (which is the default) or set it to 0 to remove the limit completely
Save the file
Restart CSF, in SSH run:
csf -r
