Alerting if no syslog received

Hello,

I was looking for a solution to generate an alert if there’s no syslog received from device for a specified period of time.

Implied logic:

IF 
    no syslog received last 24 hours
THEN
    generate alert

Have tried with something like syslog.timestamp != macros.past_5m but that doesn’t work as expected. Maybe I’m misunderstanding something here.

I believe I’m missing something too obvious here or this requirement is just not applicable in LibreNMS.

Will appreciate any thoughts on this.
Thanks.