Nagios is a host and service monitoring tool designed to inform systems administrators of network problems before clients or managers notice. Nagios makes it possible to continuously monitor network services (like SMTP, POP3, HTTP, NNTP, PING), host resources (such as processor load, disk and memory usage, running processes, and log files), and environmental factors (like temperature). Nagios: System and Network Monitoring, 2nd Edition is completely revised and expanded with over 200 pages of new material. Readers will find up-to-date coverage of the Nagios core and all standard Nagios plug-ins and will learn how to write their own plug-ins. The book also includes a new approach to building a customized Nagios website using NDOUtils, how to use the NagVis add-on to view the health of systems on a map, and lots of hands-on information on how to improve Nagios performance. A completely rewritten chapter on how to monitor Windows machines, detailed descriptions of macros, and help with migrating from 2.x to 3.0 round out the book. This book is co-published with Open Source Press.