MRTG Configuration in Debian

What is MRTG?

The Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic load on network links. MRTG generates HTML pages containing PNG images which provide a LIVE visual representation of this traffic.

Download MRTG

MRTG Documentation

First you need to install apache2 webserver for this click here

Now we need to install mrtg and snmp

Installing MRTG in Debian

#apt-get install mrtg snmpd

The installation will create an mrtg subdirectory where the Apache Web pages reside. On your Debian system the path of this subdirectory is:


Now you need to edit the mrtg configuration file to edit the some of the settings

File is located at /etc/mrtg.cfg you need to change the global settings as follows

# Global Settings

RunAsDaemon: yes
EnableIPv6: no
WorkDir: /var/www/mrtg
Options[_]: bits,growright
WriteExpires: Yes

Title[^]: Traffic Analysis for

You will find a crontab running every 5 minutes as user root

# cat /etc/cron.d/mrtg
0-55/5 * * * * root if [ -x /usr/bin/mrtg ] && [ -r /etc/mrtg.cfg ]; then env LANG=C /usr/bin/mrtg /etc/mrtg.cfg >> /var/log/mrtg/mrtg.log 2>&1; fi

Now we need to assign the snmp community name in snmp configration file /etc/snmp/snmpd.conf

# source community
# com2sec paranoid default public
com2sec readonly default public
#com2sec readwrite default private

Now you need to restart the snmp service

#/etc/init.d/snmpd restrat

The configuration file creating using

#cfgmaker [email protected] > /etc/mrtg.cfg

Creating a configuration file for a device using

#cfgmaker [email protected] >> /etc/mrtg.cfg

With the configuration file created correctly there's only one other thing you have to do and that's to use the indexmaker utility to create the summary home page. Since you have to re-run this command every time you make certain changes to the /etc/mrtg.cfg configuration file,

Creating index file for the webserver using

#indexmaker /etc/mrtg.cfg > /var/www/mrtg/index.html

Now you need to reboot your system wait for five minutes or so and then take a look at your summary home page. If your Debian system's IP address is then you'd type in the following in the address bar of a browser running on a system on the same network:

Your summary home page should come up with a graph for each target entry in the configuration file. If a graph looks like there's no data on it, click on it and check the statistics to see if any traffic is being seen. Small amounts of traffic won't show up on the graphs because we used the Unscaled statement

Some of examples how to monitor cpu and memory usage

CPU Usage


WorkDir: /var/www/localhost/htdocs/mrtg
LoadMIBs: /usr/share/snmp/mibs/UCD-SNMP-MIB.txt
Target[localhost.cpu]:ssCpuRawUser.0&ssCpuRawUser.0:[email protected]+ ssCpuRawSystem.0&ssCpuRawSystem.0:[email protected]+
ssCpuRawNice.0&ssCpuRawNice.0:[email protected]
RouterUptime[localhost.cpu]: [email protected]
MaxBytes[localhost.cpu]: 100
Title[localhost.cpu]: CPU Load
PageTop[localhost.cpu]: <H1>Active CPU Load %</H1>
Unscaled[localhost.cpu]: ymwd
ShortLegend[localhost.cpu]: %
YLegend[localhost.cpu]: CPU Utilization
Legend1[localhost.cpu]: Active CPU in % (Load)
LegendI[localhost.cpu]: Active
Options[localhost.cpu]: growright,nopercent

Memory Usage


LoadMIBs: /usr/share/snmp/mibs/HOST-RESOURCES-MIB.txt
Target[localhost.mem]: .[email protected]
PageTop[localhost.mem]: <H1>Free Memory</H1>
WorkDir: /var/www/localhost/htdocs/mrtg
Options[localhost.mem]: nopercent,growright,gauge,noinfo
Title[localhost.mem]: Free Memory
MaxBytes[localhost.mem]: 1000000
kMG[localhost.mem]: k,M,G,T,P,X
YLegend[localhost.mem]: bytes
ShortLegend[localhost.mem]: bytes
LegendI[localhost.mem]: Free Memory:
Legend1[localhost.mem]: Free memory, not including swap, in bytes

Creating jobs for the above two examples



/usr/bin/mrtg /etc/mrtg/cpu.cfg



/usr/bin/mrtg /etc/mrtg/mem.cfg

Run each script 3 times (disregard the warnings)


Make the Index Files

#/usr/bin/indexmaker --output=/var/www/mrtg/index.html \
--title="Memory and CPU Usage :)" \
--sort=name \
--enumerate \
/etc/mrtg/cpu.cfg \

Make the mrtg.cfg file

#cfgmaker --global "WorkDir: /var/www/mrtg/" \
--global "Options[_]: growright,bits" \
--ifref=ip \
[email protected] > /etc/mrtg/mrtg.conf

Cronjob setup

/bin/cat >> /var/spool/cron/crontabs/root
*/5 * * * * /bin/run-parts /etc/cron.mrtg 1> /dev/null

Now you logon to your web browser and check you should see the graphs