Rules are defined using a logical language. The GUI provides a simple way of creating basic rules. Creating more complicated rules which may include maths calculations and MySQL queries can be done using macros

Video on how the alert rules work in LibreNMS

Alert Rules

Video on how to use alert rule with wildcards

Alert Rules wildcard


Rules must consist of at least 3 elements: An Entity, a Condition and a Value. Rules can contain braces and Glues. Entities are provided from Table and Field from the database. For Example: %ports.ifOperStatus.

Please note that % is not required when adding alert rules via the WebUI. Conditions can be any of:

Values can be an entity or any single-quoted data. Glues can be && for AND.

Note if you need to use OR || please use a macros

Note: The difference between Equals and Like (and its negation) is that Equals does a strict comparison and Like allows the usage of MySQL RegExp.

Arithmetics are allowed as well.


Here are some of the other options available when adding an alerting rule:


You can associate a rule to a procedure by giving the URL of the procedure when creating the rule. Only links like "http://" are supported, otherwise an error will be returned. Once configured, procedure can be opened from the Alert widget through the "Open" button, which can be shown/hidden from the widget configuration box.


Alert when:

Alert Rules Collection

You can also select Alert Rule from the Alerts Collection. These Alert Rules are submitted by users in the community :) If would like to submit your alert rules to the collection, please submit them here Alert Rules Collection Alert Rules Collection