NodeWatch is an open source TCP/IP network monitoring tool written in Perl for UNIX. It will watch, i.e. poll, a set of network nodes and react to node connectivity changes by making entries to the syslog and executing user defined commands. NodeWatch was written from the perspective of a network manager; it only keeps track of the node's ability to respond to ICMP echo request datagrams with ICMP echo reply datagrams.
Obtaining the Software
NodeWatch is available via HTTP. It requires Perl, version 5.8.1 or later. QuickPage makes a superb adjunct to NodeWatch's capabilities.
See the documentation page for a detailed discussion of how NodeWatch works and how to configure it. Default values are kept in the daemon itself. There is a configuration file, and if NodeWatch can't find it, then the defaults are used. Otherwise the values in the configuration file are used. Beyond the configuration file, there are three other files requiring configuration: the node database, the period database, and the action database. There is a description in the manual and hints in each database.
Starting NodeWatch is simple: run it. It is a daemon, and doesn't recognize any command line arguments. It will automatically recognize changes in configuration files, so there is no need to send it a signal to reload its configuration data -- control its operational behavior through the use of flags in its primary 'options' configuration file.
There are several tools included in the distribution, including gag-nodewatch, which provides a command-line tool for editing the textual 'monitored node' database, and debug-nodewatch, which provides a command-line tool for setting the Debug Level parameter in the primary 'options' file.
The foremost support is the manual page, comments in the configuration files, and the daemon itself. Also, the current maintainer will respond to queries, time permitting.
Comments or questions regarding NodeWatch are welcome. Please direct feedback to the maintainer.
Ron Hood wrote the first version of NodeWatch in 1994; the core design and principles remain his creation. In 1996, Patrick Ryan rewrote NodeWatch from scratch, adding many features. In the fall of 2000, Stuart Kendrick adopted the role of maintainer
Last modified: 2015-January-04