MRTG(1) 							       mrtg								   MRTG(1)

NAME

       mrtg - What is MRTG ?

DESCRIPTION

       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. Check http://www.stat.ee.ethz.ch/mrtg/ to see what it does.

       Go to
	http://oss.oetiker.ch/mrtg for all the details about mrtg.

HIGHLIGHTS

       Portable
	   MRTG works on most UNIX platforms and Windows NT.

       Perl
	   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
	   external SNMP package.

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

       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 of configuration tools which make configuration and setup very simple.

       Performance
	   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.

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

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

DETAILS

       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 monitored 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 representations of the traffic seen during the last seven days, the last
       five 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.  Therefore 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
       program 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.

HISTORY

       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 that showed 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 wouldn't be in this state if it hadn't been for the great contributions and
       support I received from of many people. I would like to take this opportunity to thank them all. (See the files CHANGES for a long list of
       folk people who helped to make MRTG what it is today.)

Command-line
       Mrtg is also the name of the script you have to run to poll data and generate the graphs. Most configuration is set through the
       configuration file; some command-line options exist all the same.

       --user username	and --group groupname
	   Run as the given user and/or group. (Unix Only)

       --lock-file filename
	   Use an alternate lock-file (the default is to use the configuration-file appended with "_l").

       --confcache-file filename
	   Use an alternate confcache-file (the default is to use the configuration-file appended with ".ok")

       --logging filename|eventlog
	   If this is set to writable filename, all output from mrtg (warnings, debug messages, errors) will go to filename. If you are running on
	   Win32 you can specify eventlog instead of a filename which will send all error to the windows event log.

	   NOTE:Note, there is no Message DLL for mrtg. This has the side effect that the windows event logger will display a nice message with
	   every entry in the event log, complaing about the fact that mrtg has no message dll. If any of the Windows folks want to contribute
	   one, they are welcome.

       --daemon
	   Put MRTG into the background, running as a daemon. This works the same way as the config file option, but the switch is required for
	   proper FHS operation (because /var/run is writable only by root)

       --fhs
	   Configure all mrtg paths to conform to the FHS specification; http://www.pathname.com/fhs/

       --check
	   Only check the cfg file for errors. Do not do anything.

       --pid-file=s
	   Define the name and path of the pid file for mrtg running as a daemon

       --log-only
	   Only update the logfile, do not produce graphics or html pages

       --debug=s
	   Enable debug options. The argument of the debug option is a comma separated list of debug values:

	    cfg  - watch the config file reading
	    dir  - directory mangeling
	    base - basic program flow
	    tarp - target parser
	    snpo - snmp polling
	    fork - forking view
	    time - some timing info
	    log  - logging of data via rateup or rrdtool

	   Example:

	    --debug="cfg,snpo"

READ ON

       Learn more about MRTG by going to the mrtg home page on: http://oss.oetiker.ch/mrtg

AUTHOR

       Tobias Oetiker <tobi@oetiker.ch> and many contributors

2.17.4								    2012-01-12								   MRTG(1)