Linux Server Hacks, Volume Two

Hack #79. Monitor Network Traffic with MRTG

The Multi-Router Traffic Grapher provides a quick visual snapshot of network traffic, making it easy to find and resolve congestion.

There are many reasons it's a good idea to capture data pertaining to your network and bandwidth usage. Detailed visual representations of such data can be incredibly useful in determining the causes of network outages, bottlenecks, and other issues. Collecting such detailed data used to require sophisticated and expensive equipment, but with the advent of Linux and the widespread use of SNMP, we now have a new tool to simplify and expand the possibilities of bandwidth monitoring. This tool is called the Multi-Router Traffic Grapher (MRTG), and this hack shows you how to set it up and use it.

Requirements

MRTG has a few simple dependencies that you may need to fulfill before you dive right into the installation. For starters, you need to have a web server up and running. Apache is typically recommended, but you may be able to get it to work with other web servers. You'll also need Perl installed and working on your system, and MRTG will require three libraries to build its graphs. The first, gd, is used to generate the graphs that make MRTG what it is. The second is libpng, which is used to generate the images of the graphs. Finally, to compress these images, you'll need the zlib library. Download locations for all three of these libraries can be found at the MRTG home page (http://people.ee.ethz.ch/~oetiker/webtools/mrtg/ ...