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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.

       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

2.17.10				  2022-01-19			       MRTG(1)

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