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.

       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,
           complaining 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/>. The following default values are assumed:

            confcachefile - /var/lib/mrtg/mrtg.ok
            pid-file      - /run/mrtg/mrtg.pid
            lock-file     - /var/lock/mrtg/mrtg.lck
            log-file      - /var/log/mrtg/mrtg.log

       --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