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ISBN : 978-2-7460-9712-4
EAN : 9782746097124
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CentOS 2.1AS







unix-guide − Instructions for running MRTG 2.9.5 on a Unix Box


MRTG comes to you in Source Code. This means that you have to compile parts of it before you can use it on a Unix machine. These instructions help you to do so.


In order to compile and use mrtg you need a C compiler and a copy of perl installed on your machine. In most cases this will already be available. In case it is not, here are some starting points. Below I’ll give you a detailed run through the whole compilation process.


The GNU C compiler comes pre installed on most of the free Unicies out there. For commercial Derivats you may have to download and compile it first. If you have no compiler at all there is a chicken and egg problem, but there are also precompiled versions of gcc available for most of the operating systems.



Larg parts of the MRTG system are written in the Perl scripting language. Make sure there is a recent copy of perl on your machine (try perl −v). At least version 5.005 is required for mrtg to work well. You can get the latest perl from


MRTG generates traffic graphs in the PNG format. To be able todo this it needs several 3rd party libraries. When compiling these libraries I urge you to make sure you compile them as static, non shared libraries. There is just much less trouble ahead if you are doing it like this. See the Instructions in the next section for inspiration. Note though that many free unices have all the required libraries already in place. So there is no need to install another copy. To check it is best to skip all the library instructions below and go straight into the mrtg compile.


This is a basic graph drawing library created by Thomas Boutell. Note that all releases after Version 1.3 only create PNG images. This is because a) Thomas got into trouble because the GIF format which it used to produce uses a compression technology patented by Unisys. b) PNG is more efficient and patent free. MRTG can work with old and new version of the GD library. You can get a recent copy of GD from:



Is required by gd in order to produce PNG graphics files. Get it from:



Finally is needed by libpng to compress the graphics files you create. Get a copy from


And last but not least you also need mrtg itself. In case you have not yet downloaded it, you can find a copy on my website:



In this section I will give you 1:1 instructions on how to compile the various libraries required for the compilation of mrtg. Note that these libaries may already be installed if you have a *BSD or Linux system. The wget programm used below is a simple web downloader you can also enter the address into your netscape if you don’t have wget available.

First lets create a directory for the compilation. Note that this may already exist on your system. No Problem just use it.

 mkdir -p /usr/local/src
 cd /usr/local/src

If you do not have zlib installed:

 wget http://ftp.info-zip.org/pub/infozip/zlib/zlib.tar.gz
 gunzip -c zlib.tar.gz ⎪ tar xf -
 mv zlib-?.?.?/ zlib
 cd zlib
 cd ..

If you don’t have libpng installed

 wget http://www.libpng.org/pub/png/src/libpng-1.0.8.tar.gz
 gunzip -c libpng-1.0.8.tar.gz ⎪tar xf -
 mv libpng-1.0.8 libpng
 cd libpng
 make -f scripts/makefile.std CC=gcc ZLIBLIB=../zlib ZLIBINC=../zlib
 rm *.so.* *.so
 cd ..

And now you can compile gd

 wget http://www.boutell.com/gd/http/gd-1.8.3.tar.gz
 gunzip -c gd-1.8.3.tar.gz ⎪tar xf -
 mv gd-1.8.3 gd
 cd gd

The \ characters at the end of the line mean that all the following material should actually be written on a single line.

 make INCLUDEDIRS="-I. -I../zlib -I../libpng" \
      LIBDIRS="-L../zlib -L. -L../libpng" \
      LIBS="-lgd -lpng -lz -lm"
 cd ..


Ok now everything is ready for the mrtg compilation.

 cd /usr/local
 gunzip -c mrtg-2.9.6.tar.gz ⎪ tar xvf -
 cd mrtg-2.9.6

If you all the libraries have been preinstalled on your system you can configure mrtg by doing a simple:


Otherwise you may have to give some hints on where to find the various libraries required to compile mrtg:

 ./configure --with-gd=/usr/local/src/gd      \
             --with-z=/usr/local/src/zlib     \

If you have RRDtool available you might want to tell mrtg about it so that you can opt to use rrdtool with mrtg. Check the mrtg-rrd manpage.

Configure will make sure your environment is fit for building mrtg. If it finds a problem, it will tell you so and it will also tell you what todo about it. If everything is OK , you will end up with a custom Makefile for your system. Now type:


This builds the rateup binary and edits all the perl pathnames in the scripts. All the software required by MRTG is now in the run subdirectory.

You can now safely delete the libraries we compiled above. But then again you might want to keep them around so that you have them available when compiling the next version of mrtg.


The next step is now to configure mrtg for monitoring an network device. This is done by creating an mrtg.cfg file which defines what you want to monitor. Luckily you don’t have to dive straight in and start writing your own configuration file all by yourself. Together with mrtg you also got a copy of cfgmaker. This is a script you can point at a router of your choice; and it will create a mrtg configuration file for you. You can find the script in the bin subdirectory.

 cfgmaker --global ’WorkDir: /home/httpd/mrtg’  \
          --global ’Options[_]: bits,growright’ \
          --output /home/httpd/mrtg/mrtg.cfg    \

This example above will create an mrtg config file in /home/httpd/mrtg assuming this is a directory visible on your webserver. You can read all about cfgmaker in the cfgmaker manpage. One area you might want to look at is the possibility of using --ifref=ip to prevent interface renumbering troubles from catching you.

If you want to start rolling your own mrtg configuration files, make sure you read the reference manpage to learn all about the possible configuration options.


Once you have created a configuration file, try the following:

 /usr/local/mrtg-2.9.6/bin/mrtg /home/httpd/mrtg/mrtg.cfg

This will query your router and also create your first mrtg trafic graphs and webpages. When you run mrtg for the first time there will be a lot of complaints about missing log files. Don’t worry, this is normal for the first 2 times you start mrtg. If it keeps complaining after this time you might want to look into the problem.

Starting mrtg by hand is not ideal in the long run. So when you are sattisfied with the results you must automate the process of running mrtg in regular intervals (this means every 5 minutes by default).

You can either add mrtg to your crontab with a line like this:

 0,5,10,15,20,25,30,35,40,45,50,55 * * * * \
       <mrtg-bin>/mrtg <path to mrtg-cfg>/mrtg.cfg

or if you live in Linux Land the line may look like this if you are using ’crontab −e’

*/5 * * * * <mrtg-bin>/mrtg <path to mrtg-cfg>/mrtg.cfg

or like this if you use /etc/crontab

 */5 * * * *  mrtg-user  <mrtg-bin>/mrtg <path to mrtg-cfg>/mrtg.cfg

You can also run mrtg as a daemon process by adding the line

 RunAsDaemon: Yes

to your mrtg configuration file and then creating a startup script in your system startup sequence. Unfortunately, adding startup scripts differs widely amongst different unix systems. The modern ones normally have a directory called /etc/inid.d or /etc/rc.d/init.d where you put scripts which starts the process you want to run when the system boots. Further you must create a symbolic link in /etc/rc3.d or /etc/rc.d/rc?.d called S65mrtg (this is just a sample name ... it is just important that it starts with S followed by a two digit number). If you are not sure about this, make sure you consult the documentation of your system to make sure you get this right.

A minimal script to put into init.d might look like this:

 #! /bin/sh
 cd /usr/local/mrtg-2.9.6/bin && ./mrtg --user=mrtg-user /home/httpd/mrtg/mrtg.cfg

Note that this will only work with RunAsDaemon: Yes in your mrtg.cfg file.


Tobias Oetiker <oetiker@ee.ethz.ch>