diff --git a/admin-guide/configuration/icinga2.md b/admin-guide/configuration/icinga2.md
index 3e98fb20..ea462c15 100644
--- a/admin-guide/configuration/icinga2.md
+++ b/admin-guide/configuration/icinga2.md
@@ -22,4 +22,24 @@ By default no alerts are generated. If you wish different, set
 icinga2::alerting::enable: true
 ```
 
+## Icinga2 Agent
 
+The Icinga2 Agent can be enabled with
+```
+icinga2::agent::enable: true
+```
+
+## Default Checks
+
+By default we already run a comprehensive set of checks. Some of them can be fine-tuned in Hiera.
+Whenever you have a use case which is not covered yet, please talk to us.
+
+### Kernel Ring Buffer (dmesg)
+
+This check alerts on critical kernel messages.
+But if the message as such is OK, it can be ignored by adding a substring of it to the array `icinga2::agent::check::dmesg::ignore_list` in Hiera:
+
+```
+icinga2::agent::check::dmesg::ignore_list:
+  - 'SMBus base address uninitialized - upgrade BIOS or use'
+```