MRTGEXT was originally written as an NLM for Novell Netware to obtain values used with the widely known MRTG (predecessor of cacti, which is the base of op5 Statistics), but it can also be polled from Monitor.
Agents
Windows Syslog Agent
op5 Syslog Agent runs as a service under Windows 2000, Windows XP and Windows 2003. It formats all five types of Windows Eventlog entries into syslog format and sends them to a syslog host (The op5 Monitor server or the op5 Logserver). The agent can also forward plain text log-files.
Nagios Remote Plugin Executor (NRPE)
NRPE is a Unix client for executing plugins on remote hosts. It is distributed both as rpm-packages and as portable source-code and compiles on AIX, HP-UX 11, HP-UX 10, GNU/Linux, NetBSD, FreeBSD, OpenBSD, Windows (using Cygwin), IRIX, SCO Unix, OpenVMS, MacOSX, Solaris and SunOS. NRPE is used in combination with a set of local plugins.
NSClient++
NSClient++ is the agent used for monitoring Windows type operating systems. This agent has the ability to function as a drop in replacement for NSClient providing the same features as NSClient combined with the ability to execute scripts on the monitored Windows server. In short, it provides both NSClient and NRPE_NT functionality.
Nagstamon System Tray Status Agent
Nagstamon is a Windows/Linux/OSX utility that displays the status of the op5 monitor in the form of a floating icon or system tray icon. The utility also provide links to the monitor server as well as to hosts and services that are currently experiencing problems.