MRTG(1)                              mrtg                              MRTG(1)

       mrtg - What is MRTG

       The Multi Router Traffic Grapher (MRTG) is a tool to monitor the traf-
       fic load on network-links.  MRTG generates HTML pages containing GIF
       images which provide a LIVE visual representation of this traffic.
       Check to see what it does.

       Go to for all the
       details about mrtg.

       MRTG is written in Perl and C and works under UNIX and Windows NT. MRTG
       is being successfully used on many sites around the net.  Check the
       MRTG-Site-Map on:

           MRTG works on most UNIX platforms and Windows NT.

           MRTG is written in perl and comes with full source.

       Portable SNMP
           MRTG Uses a highly portable SNMP implementation written entirely in
           Perl thanks to Simon Leinen. There is no need to install any exter-
           nal SNMP package.

       SNMPv2c support
           MRTG can read the new SNMPv2c 64bit counters. No more counter wrap-

       Reliable Interface Identification
           Router interfaces can be identified by IP address, Description and
           Ethernet address in addition to the normal Interface number.

       Constant size Logfiles
           MRTG's logfiles do NOT grow. Thanks to the use of a unique data
           consolidation algorithm.

       Automatic Configuration
           MRTG comes with a set configuration tools which make configuration
           and setup very simple.

           Time critical routines are written in C thanks to the initiative of
           Dave Rand my Co-Author.

       GIF free Graphics
           Graphics are generated directly in PNG format, using the GD library
           by Thomas Boutell.

           The look of the webpages produced by MRTG is highly configurable.

           MRTG has built in hooks for using RRDtool. If you are straped for
           performance this may help.

       MRTG consists of a Perl script which uses SNMP to read the traffic
       counters of your routers and a fast C program which logs the traffic
       data and creates beautiful graphs representing the traffic on the moni-
       tored network connection. These graphs are embedded into webpages which
       can be viewed from any modern Web-browser.

       In addition to a detailed daily view, MRTG also creates visual repre-
       sentations of the traffic seen during the last seven days, the last
       four weeks and the last twelve months. This is possible because MRTG
       keeps a log of all the data it has pulled from the router. This log is
       automatically consolidated, so that it does not grow over time, but
       still contains all the relevant data for all the traffic seen over the
       last two years.  This is all performed in an efficient manner.  There-
       fore you can monitor 200 or more network links from any halfway decent
       UNIX box.

       MRTG is not limited to monitoring traffic though, it is possible to
       monitor any SNMP variable you choose. You can even use an external pro-
       gram to gather the data which should be monitored via MRTG. People are
       using MRTG, to monitor things such as System Load, Login Sessions,
       Modem availability and more. MRTG even allows you to accumulate two or
       more data sources into a single graph.

       In 1994 I was working at a site where we had one 64kbit line to the
       outside world. Obviously everybody was interested in knowing how the
       link was performing. So I wrote a quick hack which created a constantly
       updated graph on the web, showing the traffic load on our Internet
       link. This eventually evolved into a rather configurable Perl script
       called MRTG-1.0 which I released in spring 1995. After a few updates I
       left my job at DMU, to start work at the Swiss Federal Institute of
       Technology. Due to lack of time I had to put MRTG aside. One day in
       January of 1996, I received email from Dave Rand asking if I had any
       ideas why MRTG was so slow. Actually I did. MRTG's programming was not
       very efficient and it was written entirely in Perl. After a week or so,
       Dave wrote back to me and said he had tried what I had suggested for
       improving MRTG's speed. Since the changes did not help much, he had
       decided to rewrite the time-critical sections of MRTG in C. The code
       was attached to his email. His tool increased the speed of MRTG by a
       factor of 40! This got me out of my 'MRTG ignorance' and I started to
       spend my spare time developing of MRTG-2.

       Soon after MRTG-2 development had begun I started to give beta copies
       to interested parties. In return I got many feature patches, a lot of
       user feedback and bug fixes. The product you are getting now is wouldnt
       be in this state if it hadn't been for the great contributions and
       suport I received from of many people. I would like to take this oppor-
       tunity to thank them all. (See the files CHANGES for a long list of
       folk people who helped to make MRTG what it is today)

       Learn more about MRTG by going to the mrtg home page on: http://peo-

       Tobias Oetiker <> and many contributors

3rd Berkeley Distribution           2.9.17                             MRTG(1)