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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.

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

HIGHLIGHTS
     Portable
	 MRTG works on most UNIX platforms and Windows NT.

     PerlMRTG 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 eth-
	 ernet 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 consoli-
	 dation 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 per-
	 formance 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 cre-
     ates 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  representa-
     tions  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 con-
     solidated 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 moni-
     tor  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 per-
     forming.  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  eventu-
     ally 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 gener-
     ate 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  configura-
	 tion-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 as-
	 sumed:

	  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 sepa-
	 rated 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

2.17.10 			   2022-01-19				 MRTG(1)

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