The Nagios metapackage
Nagios core - monitoring daemon, web GUI, and documentation
Official plugins for Nagios
50+ standard plugins for Icinga, Naemon, Nagios, Shinken, Sensu
Nagios plugin to monitor the values of onboard sensors and disk temperatures
Strictly RFC 3986 compliant URI parsing library in C
Modules to streamline Nagios, Icinga, Shinken, etc. plugins
A SNMP Perl Module
Perl DES encryption module
Crypt::CBC compliant Rijndael encryption module
NIST SHA message digest algorithm