### <a id="scheduling-downtime"></a> Scheduling a downtime
-This can either happen through a web interface or by sending an [external command](4-advanced-topics.md#external-commands)
+This can either happen through a web interface or by sending an [external command](5-advanced-topics.md#external-commands)
to the external command pipe provided by the `ExternalCommandListener` configuration.
Fixed downtimes require a start and end time (a duration will be ignored).
The example below uses [runtime macros](3-monitoring-basics.md#runtime-macros) and a
[global constant](19-language-reference.md#constants) named `GraphiteEnv`. The constant name
-is freely definable and should be put in the [constants.conf](5-configuring-icinga-2.md#constants-conf) file.
+is freely definable and should be put in the [constants.conf](4-configuring-icinga-2.md#constants-conf) file.
const GraphiteEnv = "icinga.env1"