UNIX-GUIDE(1) mrtg UNIX-GUIDE(1)
unix-guide - Instructions for running MRTG 2.9.17 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
GCC 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 com-
piler at all there is a chicken and egg problem, but there are also precompiled ver-
sions 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 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 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
If the first attempt fails, and you do not get a working version of mrtg, try compiling
new copies of all libraries as explained below ... Do this BEFORE you send email to me
about problems compiling mrtg.
gd 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
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 step by step 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 so that you can skip recompiling them. 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
If you do not have zlib installed:
gunzip -c zlib.tar.gz | tar xf -
mv zlib-?.?.?/ zlib
If you don't have libpng installed
gunzip -c libpng-*.tar.gz |tar xf -
mv libpng-* libpng
make -f scripts/makefile.std CC=gcc ZLIBLIB=../zlib ZLIBINC=../zlib
rm *.so.* *.so
And now you can compile gd
gunzip -c gd-1.8.3.tar.gz |tar xf -
mv gd-1.8.3 gd
The \ characters at the end of the following lines 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"
Ok now everything is ready for the mrtg compilation.
gunzip -c mrtg-2.9.17.tar.gz | tar xvf -
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 --prefix=/usr/local/mrtg-2 \
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 prob-
lem, 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. You can now
install mrtg by typing
All the software required by MRTG is now installed under in the /usr/local/mrtg-2 subdi-
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
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/mrtg/cfg/mrtg.cfg \
This example above will create an mrtg config file in /home/mrtg/cfg assuming this is a
directory visible on your webserver. You can read all about cfgmaker in the cfgmaker man-
page. 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:
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 com-
plaining 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
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 sys-
tems. The modern ones normally have a directory called /etc/init.d or /etc/rc.d/init.d
where you put scripts which starts the process you want to run when the system boots. Fur-
ther 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:
cd /usr/local/mrtg-2.9.17/bin && ./mrtg --user=mrtg-user \
/home/httpd/mrtg/mrtg.cfg --logging /var/log/mrtg.log
Note that this will only work with RunAsDaemon: Yes in your mrtg.cfg file.
Tobias Oetiker <email@example.com>
3rd Berkeley Distribution 2.9.17 UNIX-GUIDE(1)