Installing MRTG on a Windows Platform

Understanding MRTG and Its Reach

MRTG, short for Multi‑Router Traffic Grapher, is the go‑to tool for network administrators who need a simple yet powerful way to visualize traffic flow, bandwidth usage, and other SNMP‑exposed metrics. It’s open source, which means the code is freely available and community‑driven. Major enterprises - from telecom operators to large data centers - deploy MRTG to confirm that service‑level agreements are being met and to spot congestion before users notice a slowdown. If you want a snapshot of who’s using MRTG and why, the “Where, What, How” page on the project site offers a curated list of real‑world deployments.

Although MRTG originated as a router monitoring solution, its flexibility lets you feed any numeric value into the graph engine. That could be daily sales figures, temperature readings from a weather station, or even the number of active sessions on a web server. The only requirement is that the data source can be queried or supplied in a format that MRTG understands.

Because of its lightweight nature and the fact that it writes static HTML pages, MRTG is an excellent choice for monitoring on systems that may not support heavy dashboards or real‑time monitoring agents. It works well on Windows, Linux, macOS, and many other platforms. The rest of this guide will walk you through getting MRTG up and running on a Windows machine, covering the tools you’ll need, the installation steps, and how to keep the system fresh with the latest components.

One of the reasons MRTG is so popular is its ability to generate clear, line‑graph visuals that can be refreshed automatically. When you look at a page like traffic jams in the Netherlands or local temperatures in Wroclaw, you can see how MRTG translates raw SNMP data into a meaningful story. If you can present a numeric value to MRTG, the program will create a graph that updates on schedule, letting you see real‑time changes at a glance.

In the following sections, you’ll learn how to install MRTG with a pre‑packaged bundle that bundles everything you need, how to configure it for your network, and how to fine‑tune the output to match your branding and monitoring goals. By the end of this process, you’ll have a fully functional MRTG system running on your Windows platform, ready to keep an eye on your network traffic.

Gathering the Right Tools for a Smooth Installation

Getting MRTG installed on Windows is simpler than you might think if you start with a ready‑made bundle. The bundle from Open Innovations brings several key components together: a trimmed‑down RRDTool, a user‑friendly CGI script set, and a lightweight Apache server that runs on port 9191. The Apache instance keeps the main web server - whether it’s IIS or something else - unaffected, so you don’t need to lower its security settings.

Another advantage of the bundle is that it comes with a “GetIF” SNMP utility. That tool makes it straightforward to discover the correct OIDs for each interface on a router, which is a step that can otherwise feel tedious. The bundle also includes sample batch files that help automate device addition and configuration generation, making it easier to add new switches or routers later on.

While the bundle has most of what you need, you’ll still want a robust Perl interpreter to run the CGI scripts. Active State’s

During the copy process, the installer will detect the Active Perl installation. If it cannot locate Perl, it will pause and ask you to browse to the Perl binary. Locate the file “perl.exe” in the “C:\Perl\bin” folder (or wherever Active Perl placed it) and click “Open”. The installation will resume and complete the file copy. Once the copy is finished, the installer will ask if you want to use the built‑in “myrouters.txt” file to generate initial configuration files. This file is a simple list of devices in the format “community@IP”. Edit it with a text editor: replace the placeholder line with the actual community string and router IP you want to monitor. Each router should be on its own line.

After the initial configuration file is in place, the installer will launch a secondary script called “install.bat”. This batch file orchestrates the creation of configuration files, the installation of the SNMP for Windows component (SNMP4W2K), and the startup of Apache and Cron. Run “install.bat” from a command prompt in the “C:\mrtg” directory. Press ENTER to accept the welcome screen, then answer “y” when it asks whether you want to install SNMP4W2K. Enter the number of CPUs your machine has (1 or 2 is common for a server); this number influences how the SNMP daemon allocates resources.

Once SNMP4W2K is installed, the script will prompt you again to confirm that your “myrouters.txt” file exists. Respond “y” if you set it up, or “n” if you want to skip device discovery. After that, the script will ask you to verify the installation options. Confirm by typing “y”. The script will then query each router listed in the file, collect OIDs for all interfaces, and create individual .cfg files under “C:\mrtg\mrtgbin”. It will also add cron jobs that run MRTG every minute to pull fresh data from the devices.

When the process finishes, you’ll see a message stating that the installation was successful. Open a web browser and navigate to http://localhost:9191. If everything worked, you should see a page with a list of routers and a menu of graphs. This page is generated by the “routers2.cgi” script, which interprets the .cfg files and RRD databases. The graphs are static HTML pages that update every minute, so you can refresh the browser to see real‑time changes.

At this point your MRTG system is fully functional. You can use the “myrouters.txt” file to add more routers later: simply append a new line with the community and IP, then run “install.bat” again. The script will pick up the new entry and create a new configuration file automatically. For a more hands‑on approach, you can use the provided “Update_MyRouters.bat” batch file to regenerate the configuration files on the fly.

Keeping MRTG Current: Upgrading Routers2.cgi and RRDTool

The MRTG bundle ships with an older version of the routers2.cgi CGI script and a relatively dated RRDTool binary. While they work, newer releases bring bug fixes, performance improvements, and new features such as better graph scaling. To keep your dashboard looking sharp and to benefit from security patches, you should upgrade these components after the initial installation.

First, download the latest routers2.cgi from the