Zabbix 6.4 (server and agent) I am currently collecting interface byte counts on several of my servers and firewall with the net.if.in/out item type (I use a secondary item to add byte increases to a running total to avoid the total being zero'd out on reboot). For the purposes of internet bandwidth caps (which are by billing period, typically by calendar month) I want to keep track of each months total data and the current running total since the beginning of the current month. My idea so far is to have a calculated item that pulls values from the counter item and adds it to this calculated item. Then, on the 1st day of every month, the calculated item's value would be set back to zero. Could this be done through the formular section, or maybe a preprocessing step with javascript, or maybe a whole separate trigger? I am unsure how I can alter an items value based on a time period?