Nagios allows you to enter one or more comments for a host or a service. These can be anything from 'Third machine from top on the left shelf' to 'Reset button not working'. Nagios also adds comments automatically in several cases. For example, when an object is scheduled for downtime, a comment is created stating this.

Comments associated with a specific object are shown on the host or service detail information pages(as appropriate). Comments can also be added and removed via these pages.

Nagios also offers a page that allows you to manage comments for all hosts and services, similar to how you manage scheduled downtimes. This page allows you to add or delete comments for all hosts. You can also navigate to the detailed information page for a host or service by clicking on the object's name. This page can be accessed via the Comments link on the left-side menu.

The following is a screenshot of the comments page:

Clicking on the 'trash' icon next to any comment will delete...