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MRTG-REFERENCE(1)		     mrtg		     MRTG-REFERENCE(1)

       mrtg-reference - MRTG 2.14.7 configuration reference

       The runtime behaviour of MRTG is governed by a configuration file.
       Run-of- ther-mill configuration files can be generated with cfgmaker.
       (Check cfgmaker). But for more elaborate configurations some hand-tun
       ing is required.

       This document describes all the configuration options understood by the
       mrtg software.

       MRTG configuration file syntax follows some simple rules:

	  Keywords must start at the beginning of a line.

	  Lines which follow a keyword line which start with a blank are
	   appended to the keyword line

	  Empty Lines are ignored

	  Lines starting with a # sign are comments.

	  You can add other files into the configuration file using

	   Include: file


	    Include: base-options.inc

	   If included files are specified with relative paths, both the cur
	   rent working directory and the directory containing the main config
	   file will be searched for the files.


       WorkDir specifies where the logfiles and the webpages should be cre


	WorkDir: /usr/tardis/pub/www/stats/mrtg


       HtmlDir specifies the directory where the html (or shtml, but well get
       on to those later) lives.

       NOTE: Workdir overrides the settings for htmldir, imagedir and logdir.


	Htmldir: /www/mrtg/


       ImageDir specifies the directory where the images live. They should be
       under the html directory.


	Imagedir: /www/mrtg/images


       LogDir specifies the directory where the logs are stored.  This need
       not be under htmldir directive.


	Logdir: /www/mrtg/logs

       Forks (UNIX only)

       With system that supports fork (UNIX for example), mrtg can fork itself
       into multiple instances while it is acquiring data via snmp.

       For situations with high latency or a great number of devices this will
       speed things up considerably. It will not make things faster, though,
       if you query a single switch sitting next door.

       As far as I know NT can not fork so this option is not available on NT.


	Forks: 4


       When set to yes, IPv6 support is enabled if the required libraries are
       present (see the mrtg-ipv6 manpage). When IPv6 is enabled, mrtg can
       talk to routers using SNMP over IPv6 and targets may be specified by
       their numeric IPv6 addresses as well as by hostname or IPv4 address.

       If IPv6 is enabled and the target is a hostname, mrtg will try to
       resolve the hostname to an IPv6 address and, if this fails, to an IPv4
       address.  Note that mrtg will only use IPv4 if you specify an IPv4
       address or a hostname with no corresponding IPv6 address; it will not
       fall back to IPv4 if it simply fails to communicate with the target
       using IPv6. This is by design.

       Note that many routers do not currently support SNMP over IPv6. Use the
       IPv4Only per target option for these routers.

       IPv6 is disabled by default.


	EnableIPv6: Yes


       When set to yes, uses the Net::SNMP module instead of the SNMP_SESSION
       module for generating snmp queries.  This allows the use of SNMPv3 if
       other snmpv3 parameters are set.

       SNMPv3 is disabled by default.


	EnableSnmpV3: yes


       How many seconds apart should the browser (Netscape) be instructed to
       reload the page? If this is not defined, the default is 300 seconds (5


	Refresh: 600


       How often do you call mrtg? The default is 5 minutes. If you call it
       less often, you should specify it here.	This does two things:

	  The generated HTML page contains the right information about the
	   calling interval ...

	  A META header in the generated HTML page will instruct caches about
	   the time-to-live of this page .....

       In this example, we tell mrtg that we will be calling it every 10 min
       utes. If you are calling mrtg every 5 minutes, you can leave this line
       commented out.


	Interval: 10

       Note that unless you are using rrdtool you can not set Interval to less
       than 5 minutes. If you are using rrdtool you can set interval down to 1
       minute. Note though, setting the Interval for an rrdtool/mrtg setup
       will influence the initial creation of the database. If you change the
       interval later, all existing databases will remain at the resolution
       they were initially created with.


       MRTG relies heavily on the real time clock of your computer. If the
       time is set to a wrong value, especially if it is advanced far into the
       future, this will cause mrtg to expire lots of supposedly old data from
       the log files.

       To prevent this, you can add a reasonability check by specifying a
       maximum age for log files. If a file seems to be older, mrtg will not
       touch it but complain instead, giving you a chance to investigate the


	MaxAge: 7200

       The example above will make mrtg refuse to update log files older than
       2 hours (7200 seconds).


       With this switch mrtg will generate .meta files for CERN and Apache
       servers which contain Expiration tags for the html and gif files. The
       *.meta files will be created in the same directory as the other files,
       so you will have to set "MetaDir ." and "MetaFiles on" in your
       apache.conf or .htaccess file for this to work

       NOTE: If you are running Apache-1.2 or later, you can use the
       mod_expire to achieve the same effect ... see the file htaccess.txt


	WriteExpires: Yes


       Normally we ask the SNMP device for sysUptime and sysName proper
       ties.  Some do not have these. If you want to avoid getting complaints
       from mrtg about these missing properties, specify the nomib2 option.

       An example of agents which do not implement base mib2 attributes are
       Computer Associates - Unicenter TNG Agents.  CA relies on using the
       base OS SNMP agent in addition to its own agents to supplement the man
       agement of a system.


	NoMib2: Yes


       Some SNMP implementations can not deal with requests asking for multi
       ple snmp variables in one go. Set this in your cfg file to force mrtg
       to only ask for one variable per request.


	SingleRequest: Yes


       Apart from the per target timeout options, you can also configure the
       behaviour of the snmpget process on a more profound level. SnmpOptions
       accepts a hash of options. The following options are currently sup

	timeout 		  => $default_timeout,
	retries 		  => $default_retries,
	backoff 		  => $default_backoff,
	default_max_repetitions   => $max_repetitions,
	use_16bit_request_ids	  => 1,
	lenient_source_port_matching => 0,
	lenient_source_address_matching => 1

       The values behind the options indicate the current default value.  Note
       that these settings OVERRIDE the per target timeout settings.

       A per-target SnmpOptions[] keyword will override the global settings.
       That keyword is primarily for SNMPv3.

       The 16bit request ids are the only way to query the broken SNMP imple
       mentation of SMC Barricade routers.


	SnmpOptions: retries => 2, only_ip_address_matching => 0

       Note that AS/400 snmp seems to be broken in a way which prevents mrtg
       from working with it unless

	SnmpOptions: lenient_source_port_matching => 1

       is set.


       If you want to keep the mrtg icons in someplace other than the working
       (or imagedir) directory, use the IconDir variable for defining the url
       of the icons directory.


	IconDir: /mrtgicons/


       Load the MIB file(s) specified and make its OIDs available as symbolic
       names. For better efficiancy, a cache of MIBs is maintained in the


	LoadMIBs: /dept/net/mibs/netapp.mib,/usr/local/lib/ft100m.mib


       Switch output format to the selected Language (Check the translate
       directory to see which languages are supported at the moment. In this
       directory you can also find instructions on how to create new transla

       Currently the following laguages are supported:

       big5 brazilian bulgarian catalan chinese croatian czech danish dutch
       eucjp french galician gb gb2312 german greek hungarian icelandic
       indonesia iso2022jp italian korean lithuanian malay norwegian polish
       portuguese romanian russian russian1251 serbian slovak slovenian span
       ish swedish turkish ukrainian


	Language: danish


       Setting LogFormat to rrdtool in your mrtg.cfg file enables rrdtool
       mode.  In rrdtool mode, mrtg relies on rrdtool to do its logging. See


	LogFormat: rrdtool


       If you are using rrdtool mode and your rrdtool Perl module (RRDs.pm) is
       not installed in a location where perl can find it on its own, you can
       use LibAdd to supply an appropriate path.


	LibAdd: /usr/local/rrdtool/lib/perl/


       If the rrdtool executable can not be found in the normal "PATH", you
       can use this keyword to add a suitable directory to your path.


	PathAdd: /usr/local/rrdtool/bin/


       The RunAsDaemon keyword enables daemon mode operation. The purpose of
       daemon mode is that MRTG is launched once and not repeatedly (as it is
       with cron).  This behavior saves computing resourses as loading and
       parsing of configuration files happens only once.

       Using daemon mode MRTG itself is responible for timing the measurement
       intervals. Therfore its important to set the Interval keyword to an
       apropiate value.

       Note that when using daemon mode MRTG should no longer be started from
       cron as each new process runs forever. Instead MRTG should be started
       from the command prompt or by a system startup script.

       If you want mrtg to run under a particular user and group (it is not
       recomended to run MRTG as root) then you can use the --user=user_name
       and --group=group_name options on the mrtg commandline.

	mrtg --user=mrtg_user --group=mrtg_group mrtg.cfg

       Also note that in daemon mode restarting the process is required in
       order to activate changes in the config file.

       Under UNIX, the Daemon switch causes mrtg to fork into background after
       checking its config file. On Windows NT the MRTG process will detach
       from the console, but because the NT/2000 shell waits for its children
       you have to use this special start sequence when you launch the pro

	start /b perl mrtg mrtg.cfg

       You may have to add path information equal to what you add when you run
       mrtg from the commandline.


	RunAsDaemon: Yes
	Interval:    5

       This makes MRTG run as a daemon beginning data collection every 5 min

       If you are daemontools and still want to run mrtg as a daemon you can
       additionally specify

	NoDetach:     Yes

       this will make mrtg run but without detaching it from the terminal.


       Some devices may produce non-numeric values that would nevertheless be
       useful to graph with MRTG if those values could be converted to num
       bers.  The ConversionCode keyword specifies the path to a file contain
       ing Perl code to perform such conversions. The code in this file must
       consist of one or more Perl subroutines. Each subroutine must accept a
       single string argument and return a single numeric value. When RRDtool
       is in use, a decimal value may be returned. When the name of one of
       these subroutines is specified in a target definition (see below), MRTG
       calls it twice for that target, once to convert the the input value
       being monitored and a second time to convert the output value. The sub
       routine must return an undefined value if the conversion fails. In case
       of failure, a warning may be posted to the MRTG log file using Perls
       warn function. MRTG imports the subroutines into a separate name space
       (package MRTGConversion), so the user need not worry about pollution of
       MRTGs global name space. MRTG automatically prepends this package dec
       laration to the user-supplied code.

       Example: Suppose a particular OID returns a character string whose
       length is proportional to the value to be monitored. To convert this
       string to a number that can be graphed by MRTG, create a file arbitrar
       ily named "MyConversions.pl" containing the following code:

	# Return the length of the string argument
	sub Length2Int {
	  my $value = shift;
	  return length( $value );

       Then include the following global keyword in the MRTG configuration
       file (assuming that the conversion code file is saved in the mrtg/bin
       directory along with mrtg itself):

	ConversionCode: MyConversions.pl

       This will cause MRTG to include the definition of the subroutine
       Length2Int in its execution environment. Length2Int can then be invoked
       on any target by appending "Length2Int" to the target definition as


       See "Extended Host Name Syntax" below for complete target definition
       syntax information.

       Each monitoring target must be identified by a unique name. This name
       must be appended to each parameter belonging to the same target. The
       name will also be used for naming the generated webpages, logfiles and
       images for this target.


       With the Target keyword you tell mrtg what it should monitor. The Tar
       get keyword takes arguments in a wide range of formats:

	   The most basic format is "port:community@router" This will generate
	   a traffic graph for the interface port of the host router (dns
	   name or IP address) and it will use the community community (snmp
	   password) for the snmp query.


	    Target[myrouter]: 2:public@wellfleet-fddi.domain

	   If your community contains a "@" or a " " these characters must be
	   escaped with a "\".

	    Target[bla]: 2:stu\ pi\@d@router

	   If you have a fast router you might want to try to poll the ifHC*
	   counters.  This feature gets activated by switching to SNMPv2c.
	   Unfortunately not all devices support SNMPv2c yet. If it works,
	   this will prevent your counters from wraping within the 5 minute
	   polling interval, since we now use 64 bit instead of the normal 32


	    Target[myrouter]: 2:public@router1:::::2

	   As an alternative to SNMPv2c, SNMPv3 provides access to the ifHC*
	   counters, along with encryption.  Not all devices support SNMPv3,
	   and you will also need the perl Net::SNMP library in order to use
	   it.	It is recommended that cfgmaker be used to generate configura
	   tions involving SNMPv3, as it will check if the Net::SNMP library
	   is loadable, and will switch to SNMPv2c if v3 is unavailable.

	   SNMP v3 requires additional authentication parameters, passed using
	   the SnmpOptions[] per-target keyword.

	     Target[myrouter]: 2:router1:::::3
	     SnmpOptions[myrouter]: username=>user1

	   Sometimes you are sitting on the wrong side of the link, and you
	   would like to have mrtg report Incoming traffic as Outgoing and
	   vice versa. This can be achieved by adding the - sign in front of
	   the "Target" description. It flips the incoming and outgoing traf
	   fic rates.


	    Target[ezci]: -1:public@ezci-ether.domain

       Explicit OIDs
	   You can also explicitly define which OID to query by using the fol
	   lowing syntax OID_1&OID_2:community@router The following example
	   will retrieve error counts for input and output on interface 1.
	   MRTG needs to graph two variables, so you need to specify two OIDs
	   such as temperature and humidity or error input and error output.



       MIB Variables
	   MRTG knows a number of symbolic SNMP variable names.  See the file
	   mibhelp.txt for a list of known names.  One example are the ifIn
	   Errors and ifOutErrors.  This means you can specify the above as:


	    Target[myrouter]: ifInErrors.1&ifOutErrors.1:public@myrouter

	   It may be that you want to monitor an snmp object that is only
	   reachable by walking. You can get mrtg to walk by prepending the
	   OID with the string WaLK or if you want a particular entry from the
	   table returned by the walk you can use WaLKx where x is a number
	   starting from 0 (!).


	     Target[myrouter]: WaLKstrangeOid.1&WaLKstrangeOid.2:public@myrouter

	     Target[myrouter]: WaLK3strangeOid.1&WaLK4strangeOid.2:public@myrouter

       Interface by IP
	   Sometimes SNMP interface index can change, like when new interfaces
	   are added or removed. This can cause all Target entries in your
	   config file to become offset, causing MRTG to graphs wrong
	   instances etc.  MRTG supports IP address instead of ifindex in tar
	   get definition. Then MRTG will query snmp device and try to map IP
	   address to the current ifindex.  You can use IP addresses in every
	   type of target definition by adding IP address of the numbered
	   interface after OID and separation char /.

	   Make sure that the given IP address is used on your same target
	   router, especially when graphing two different OIDs and/or inter
	   face split by & delimiter.

	   You can tell cfgmaker to generate such references with the option


	    Target[myrouter]: /
	    Target[ezci]: -/
	    Target[myrouter]: ifInErrors/

       Interface by Description
	   If you can not use IP addresses you might want to use the interface
	   names. This works similar to the IP address aproach except that the
	   prefix to use is a \ instead of a /

	   You can tell cfgmaker to generate such references with the option


	    Target[myrouter]: \My-Interface2:public@wellfleet-fddi.domain
	    Target[ezci]: -\My-Interface2:public@ezci-ether.domain
	    Target[myrouter]: ifInErrors\My-Interface2&ifOutErrors\My-Interface3:public@myrouter

	   If your description contains a "&", a ":", a "@" or a " " you can
	   include them but you must escape with a backlash:

	    Target[myrouter]: \fun\:\ ney\&ddd:public@hello.router

       Interface by Name
	   This is the only sensible way to reference the interfaces of your

	   You can tell cfgmaker to generate such references with the option


	    Target[myrouter]: #2/11:public@wellfleet-fddi.domain
	    Target[ezci]: -#2/11:public@ezci-ether.domain
	    Target[myrouter]: ifInErrors#3/7&ifOutErrors#3/7:public@myrouter

	   If your description contains a "&", a ":", a "@" or a " " you can
	   include them but you must escape with a backlash:

	    Target[myrouter]: #\:\ fun:public@hello.router

	   Note that the # sign will be interpreted as a comment character if
	   it is the first non white-space character on the line.

       Interface by Ethernet Address
	   When the SNMP interface index changes, you can key that interface
	   by its Physical Address, sometimes called a hard address, which
	   is the SNMP variable ifPhysAddress.	Internally, MRTG matches the
	   Physical Address from the *.cfg file to its current index, and then
	   uses that index for the rest of the session.

	   You can use the Physical Address in every type of target definition
	   by adding the Physical Address after the OID and the separation
	   char ! (analogous to the IP address option).  The Physical
	   address is specified as - delimited octets, such as
	   "0a-0-f1-5-23-18" (omit the double quotes). Note that some routers
	   use the same Hardware Ethernet Address for all of their Interfaces
	   which prevents unique interface identification. Mrtg will notice
	   such problems and alert you.

	   You can tell cfgmaker to generate configuration files with hardware
	   ethernet address references by using the option --ifref=eth.


	    Target[myrouter]: !0a-0b-0c-0d:public@wellfleet-fddi.domain
	    Target[ezci]: -!0-f-bb-05-71-22:public@ezci-ether.domain
	    Target[myrouter]: ifInErrors!0a-00-10-23-44-51&ifOutErrors!0a-00-10-23-44-51:public@myrouter

       Interface by Type
	   It seems that there are devices that try to defy all monitoring
	   efforts: the interesting interfaces have neither ifName nor a con
	   stant ifDescr not to mention a persistant ifIndex. The only way to
	   get a constant mapping is by looking at the interface type, because
	   the interface you are interested in is unique in the device you are
	   looking at ...

	   You can tell cfgmaker to generate such references with the option


	    Target[myrouter]: %13:public@wellfleet-fddi.domain
	    Target[ezci]: -%13:public@ezci-ether.domain
	    Target[myrouter]: ifInErrors%13&ifOutErrors%14:public@myrouter

       Extended Host Name Syntax
	   In all places where community@router is accepted, you can add
	   additional parameters for the SNMP communication using colon-sepa
	   rated suffixes. You can also append a pipe symbol (	) and the
	   name of a numeric conversion subroutine as described under the
	   global keyword "ConversionCode" above. The full syntax is as fol


	   where the meaning of each parameter is as follows:

	       the UDP port under which to contact the SNMP agent (default:

	       initial timeout for SNMP queries, in seconds (default: 2.0)

	       number of times a timed-out request will be retried (default:

	       factor by which the timeout is multiplied on every retry
	       (default: 1.0).

	       for SNMP version. If you have a fast router you might want to
	       put a 2 here.  For authenticated or encrypted SNMP, you can
	       try to put a 3 here.  This will make mrtg try to poll the 64
	       bit counters and thus prevent excessive counter wrapping. Not
	       all routers support this though.  SNMP v3 requires additional
	       setup, see SnmpOptions[] for full details.



	       the name of the subroutine that MRTG will call to convert the
	       input and output values to integers. See the complete example
	       under the global keyword "ConversionCode" above.


	       This would retrieve values from the OID for
	       input and .2 for output on mydevice using UDP port 161 and SNMP
	       version 2, and would execute the user-defined numeric conver
	       sion subroutine Length2Int to convert those values to integers.

	   A value that equals the default value can be omitted.  Trailing
	   colons can be omitted, too. The pipe symbol followed by the name
	   parameter, if present, must come at the end. There must be no
	   spaces around the colons or pipe symbol.


	     Target[ezci]: 1:public@ezci-ether.domain:9161::4

	   This would refer to the input/output octet counters for the inter
	   face with ifIndex 1 on ezci-ether.domain, as known by the SNMP
	   agent listening on UDP port 9161.  The standard initial timeout
	   (2.0 seconds) is used, but the number of retries is set to four.
	   The backoff value is the default.

       Numeric IPv6 addresses
	   If IPv6 is enabled you may also specify a target using its IPv6
	   address. To avoid ambiguity with the port number, numeric IPv6
	   addresses must be placed in square brackets.


	    Target[IPv6test]: 2:public@[2001:760:4::]:6161::4

       External Monitoring Scripts
	   If you want to monitor something which does not provide data via
	   snmp you can use some external program to do the data gathering.

	   The external command must return 4 lines of output:

	   Line 1
	       current state of the first variable, normally incoming bytes

	   Line 2
	       current state of the second variable, normally outgoing bytes

	   Line 3
	       string (in any human readable format), telling the uptime of
	       the target.

	   Line 4
	       string, telling the name of the target.

	   Depending on the type of data your script returns you might want to
	   use the gauge or absolute arguments for the Options keyword.


	    Target[myrouter]: /usr/local/bin/df2mrtg /dev/dsk/c0t2d0s0

	   Note the use of the backticks (), not apostrophes () around the

	   If you want to use a backtick in the command name this can be done
	   but you must escape it with a backslash ...

	   If your script does not have any data to return but does not want
	   mrtg to complain about invalid data, it can return UNKNOWN
	   instead of a number.  Note though that only rrdtool is realy
	   equipped to handle unknown data well.

       Multi Target Syntax
	   You can also combine several target definitions in a mathematical
	   expression.	Any syntactically correct expression that the Perl
	   interpreter can evaluate to will work. An expression could be used,
	   for example, to aggregate both B channels in an ISDN connection or
	   to calculate the percentage hard disk utilization of a server from
	   the absolute used space and total capacity.


	    Target[myrouter]: 2:public@wellfleetA + 1:public@wellfleetA

	    Target[myrouter]: / * 100

	   Note that whitespace must surround each target definition in the
	   expression.	Target definitions themselves must not contain whites
	   pace, except in interface descriptions and interface names, where
	   each whitespace character is escaped by a backslash.

	   MRTG automatically rounds the result of the expression to an inte
	   ger unless RRDTool logging is in use and the gauge option is in
	   effect for the target.  Internally MRTG uses Perls Math::BigFloat
	   package to calculate the result of the expression with 40 digits of
	   precision. Even in extreme cases, where, for example, you take the
	   difference of two 64-bit integers, the result of the expression
	   should be accurate.

       SNMP Request Optimization
	   MRTG is designed to economize on its SNMP requests. Where a target
	   definition appears more than once in the configuration file, MRTG
	   requests the data from the device only once per round of data col
	   lection and uses the collected data for each instance of a particu
	   lar target. Recognition of two target definitions as being identi
	   cal is based on a simple string match rather than any kind of
	   deeper semantic analysis.


	    Target[Targ1]: 1:public@CiscoA
	    Target[Targ2]: 2:public@CiscoA
	    Target[Targ3]: 1:public@CiscoA + 2:public@CiscoA
	    Target[Targ4]: 1:public@CISCOA

	   This results in a total of three SNMP requests. Data for 1:pub
	   lic@CiscoA and 2:public@CiscoA are requested only once each, and
	   used for Targ1, Targ2, and Targ3. Targ4 causes another SNMP request
	   for 1:public@CISCOA, which is not recognized as being identical to


       The maximum value either of the two variables monitored are allowed to
       reach. For monitoring router traffic this is normally the bytes per
       second this interface port can carry.

       If a number higher than MaxBytes is returned, it is ignored.  Also read
       the section on AbsMax for further info.	The MaxBytes value is also
       used in calculating the Y range for unscaled graphs (see the section on

       Since most links are rated in bits per second, you need to divide their
       maximum bandwidth (in bits) by eight (8) in order to get bytes per sec
       ond.  This is very important to make your unscaled graphs display real
       istic information. T1 = 193000, 56K = 7000, 10 MB Ethernet = 1250000,
       100 MB Ethernet = 12500000. The MaxBytes value will be used by mrtg to
       decide whether it got a valid response from the router.

       If you need two different MaxBytes values for the two monitored vari
       ables, you can use MaxBytes1 and MaxBytes2 instead of MaxBytes.


	MaxBytes[myrouter]: 1250000


       Title for the HTML page which gets generated for the graph.


	Title[myrouter]: Traffic Analysis for Our Nice Company


       Things to add to the top of the generated HTML page.  Note that you can
       have several lines of text as long as the first column is empty.

       Note that the continuation lines will all end up on the same line in
       the html page. If you want linebreaks in the generated html use the
       \n sequence.



Traffic Analysis for ETZ C95.1

Our Campus Backbone runs over an FDDI line\n with a maximum transfer rate of 12.5 megabytes per Second. RouterUptime In cases where you calculate the used bandwidth from several interfaces you normaly dont get the router uptime and router name displayed on the web page. If these interfaces are on the same router and the uptime and name should be displayed you have to specify its community and address again with the RouterUptime keyword. Example: Target[kacisco.comp.edu]: 1:public@ + 2:public@ RouterUptime[kacisco.comp.edu]: public@ RouterName If the default name of the router is incorrect/uninformative, you can use RouterName to specify a different OID on either the same or a dif ferent host. A practical example: sysName on BayTech DS72 units always display "ds72", no matter what you set the Unit ID to be. Instead, the Unit ID is stored at, so we can have MRTG display this instead of sysName. Example: RouterName[kacisco.comp.edu]: A different OID on a different host can also be specified: RouterName[kacisco.comp.edu]: MaxBytes1 Same as MaxBytes, for variable 1. MaxBytes2 Same as MaxBytes, for variable 2. IPv4Only Many IPv6 routers do not currently support SNMP over IPv6 and must be monitored using IPv4. The IPv4Only option forces mrtg to use IPv4 when communicating with the target, even if IPv6 is enabled. This is useful if the target is a hostname with both IPv4 and IPv6 addresses; without the IPv4Only keyword, monitoring such a router will not work if IPv6 is enabled. If set to no (the default), mrtg will use IPv6 unless the target has no IPv6 addresses, in which case it will use IPv4. If set to yes, mrtg will only use IPv4. Note that if this option is set to yes and the target does not have an IPv4 address, communication with the target will fail. This option has no effect if IPv6 is not enabled. Example: Target[v4onlyrouter_1]: 1:public@v4onlyrouter IPv4Only[v4onlyrouter_1]: Yes SnmpOptions (V3) SNMPv3 requires a fairly rich set of options. This per-target keyword allows access to the User Security Model of SNMPv3. Options are listed in the same syntax as a perl hash. Security Modes SNMPv3 has three security modes, defined on the device being polled. For example, on Cisco routers the security mode is defined by the snmp- server group global configuration command. NoAuthNoPriv Neither Authentication nor Privacy is defined. Only the Username option is specified for this mode. Example: SnmpOptions[myrouter]: username=>user1 AuthNoPriv Uses a Username and a password. The password can be hashed using the snmpkey application, or passed in plain text along with the ContextEngineID Example: SnmpOptions[myrouter]: username=>user1,authpassword=>example, contextengineid=>80000001110000004000000 Priv Both Authentication and Privacy is defined. The default privacy protocol is des. Example: SnmpOptions[myrouter]: authkey=>0x1e93ab5a396e2af234c8920e61cfe2028072c0e2, authprotocol=>sha,privprotocol=>des,username=>user1, privkey=>0x498d74940c5872ed387201d74b9b25e2 snmp options The following option keywords are recognized: username The user associated with the User Security Model contextname An SNMP agent can define multiple contexts. This keyword allows them to be polled. contextengineid A unique 24-byte string identifying the snmp-agent. authpassword The plaintext password for a user in either AuthNoPriv or Priv mode. authkey A md5 or sha hash of the plain-text password, along with the engineid. Use the snmpkey commandline program to generate this hash, or use Net::SNMP::Security::USM in a script. authprotocol {shamd5} The hashing algorithm defined on the SNMP client. Defaults to md5. privpassword A plaintext pre-shared key for encrypting snmp packets in Priv mode. privkey A hash of the plain-text pre-shared key, along with the engineid. Use the snmpkey commandline program to generate this hash, or use Net::SNMP::Security::USM in a script. privprotocol {des3desedeaescfb128aescfb192aescfb256} Specifies the encryption method defined on the snmp agent. The default is des. PageFoot Things to add to the bottom of the generated HTML page. Note that you can have several lines of text as long as the first column is empty. Note that the continuation lines will all end up on the same line in the html page. If you want linebreaks in the generated html use the \n sequence. The material will be added just before the tag: Example: PageFoot[myrouter]: Contact Peter if you have questions regarding this page AddHead Use this tag like the PageTop header, but its contents will be added between and . Example: AddHead[myrouter]: BodyTag BodyTag lets you supply your very own tag for the generated webpages. Example: BodyTag[myrouter]: AbsMax If you are monitoring a link which can handle more traffic than the MaxBytes value. Eg, a line which uses compression or some frame relay link, you can use the AbsMax keyword to give the absolute maximum value ever to be reached. We need to know this in order to sort out unreal istic values returned by the routers. If you do not set AbsMax, rateup will ignore values higher than MaxBytes. Example: AbsMax[myrouter]: 2500000 Unscaled By default each graph is scaled vertically to make the actual data vis ible even when it is much lower than MaxBytes. With the Unscaled vari able you can suppress this. Its argument is a string, containing one letter for each graph you dont want to be scaled: d=day w=week m=month y=year. There is also a special case to unset the variable completely: n=none. This could be useful in the event you need to override a global configuration. In the example scaling for the yearly and the monthly graph are suppressed. Example: Unscaled[myrouter]: ym WithPeak By default the graphs only contain the average values of the monitored variables - normally the transfer rates for incoming and outgoing traf fic. The following option instructs mrtg to display the peak 5 minute values in the [w]eekly, [m]onthly and [y]early graph. In the example we define the monthly and the yearly graph to contain peak as well as average values. Examples: WithPeak[myrouter]: ym Suppress By default mrtg produces 4 graphs. With this option you can suppress the generation of selected graphs. The option value syntax is analo gous to the above two options. In this example we suppress the yearly graph as it is quite empty in the beginning. Example: Suppress[myrouter]: y Extension By default, mrtg creates .html files. Use this option to tell mrtg to use a different extension. For example you could set the extension to php3, then you will be able to enclose PHP tags into the output (useful for getting a router name out of a database). Example: Extension[myrouter]: phtml Directory By default, mrtg puts all the files that it generates for each target (the GIFs, the HTML page, the log file, etc.) in WorkDir. If the Directory option is specified, the files are instead put into a directory under WorkDir or Log-, Image- and HtmlDir). (For example the Directory option below would cause all the files for a target myrouter to be put into directory /usr/tardis/pub/www/stats/mrtg/myrouter/ .) The directory must already exist; mrtg will not create it. Example: WorkDir: /usr/tardis/pub/www/stats/mrtg Directory[myrouter]: myrouter NOTE: the Directory option must always be relative or bad things will happen. Clonedirectory If the Directory option is specified, the Clonedirectory option will copy all the contents of Directory to the Clonedirectory. As well as the Directory option requires, the clone directory must already exist; mrtg will not create it. Example: WorkDir: /usr/tardis/pub/www/stats/mrtg Directory[myrouter]: myrouter Clonedirectory[myrouter]: myclonedirectory NOTE: the Clonedirectory option must always be relative or bad things will happen. XSize and YSize By default mrtgs graphs are 100 by 400 pixels wide (plus some more for the labels. In the example we get almost square graphs ... Note: XSize must be between 20 and 600; YSize must be larger than 20 Example: XSize[myrouter]: 300 YSize[myrouter]: 300 XZoom and YZoom If you want your graphs to have larger pixels, you can "Zoom" them. Example: XZoom[myrouter]: 2.0 YZoom[myrouter]: 2.0 XScale and YScale If you want your graphs to be actually scaled use XScale and YScale. (Beware: while this works, the results look ugly (to be frank) so if someone wants to fix this: patches are welcome. Example: XScale[myrouter]: 1.5 YScale[myrouter]: 1.5 YTics and YTicsFactor If you want to show more than 4 lines per graph, use YTics. If you want to scale the value used for the YLegend of these tics, use YTics Factor. The default value for YTics is 4 and the default value for YTicsFactor is 1.0 . Example: Suppose you get values ranging from 0 to 700. You want to plot 7 lines and want to show 0, 1, 2, 3, 4, 5, 6, 7 instead of 0, 100, 200, 300, 400, 500, 600, 700. You should write then: YTics[myrouter]: 7 YTicsFactor[myrouter]: 0.01 Factor If you want to multiply all numbers shown below the graph with a con stant factor, use this directive to define it .. Example: Factor[as400]: 4096 Step Change the default step from 5 * 60 seconds to something else (I have not tested this much ...) Example: Step[myrouter]: 60 PNGTitle When using rateup for graph generation, this will print the given title in the graph it generates. Example: PNGTitle[myrouter]: WAN Link UK-US Options The Options Keyword allows you to set some boolean switches: growright The graph grows to the left by default. This option flips the direction of growth causing the current time to be at the right edge of the graph and the history values to the left of it. bits All the monitored variable values are multiplied by 8 (i.e. shown in bits instead of bytes) ... looks much more impressive :-) It also affects the factory default labeling and units for the given target. perminute All the monitored variable values are multiplied by 60 (i.e. shown in units per minute instead of units per second) in case of small values more accurate graphs are displayed. It also affects the factory default labeling and units for the given target. perhour All the monitored variable values are multiplied by 3600 (i.e. shown in units per hour instead of units per second) in case of small values more accurate graphs are displayed. It also affects the factory default labeling and units for the given target. noinfo Suppress the information about uptime and device name in the gener ated webpage. nopercent Dont print usage percentages. transparent Make the background of the generated gifs transparent. integer Print summary lines below graph as integers without commas. dorelpercent The relative percentage of IN-traffic to OUT-traffic is calculated and displayed in the graph as an additional line. Note: Only a fixed scale is available (from 0 to 100%). Therefore if IN-traffic is greater than OUT-traffic then 100% is displayed. If you suspect that your IN-traffic is not always less than or equal to your OUT- traffic you are urged to not use this options. Note: If you use this option in combination with the Colours options, a fifth colour-name colour-value pair is required there. avgpeak There are some ISPs who use the average Peak values to bill their customers. Using this option MRTG displays these values for each graph. The value is built by averaging the max 5 minute traffic average for each step shown in the graph. For the Weekly graph this means that it builds the average of all 2 hour intervals 5 minute peak values. (Confused? Thought so!) gauge Treat the values gathered from target as current status measure ments and not as ever incrementing counters. This would be useful to monitor things like disk space, processor load, temperature, and the like ... In the absence of gauge or absolute options, MRTG treats vari ables as a counters and calculates the difference between the cur rent and the previous value and divides that by the elapsed time between the last two readings to get the value to be plotted. absolute This is for counter type data sources which reset their value when they are read. This means that rateup does not have to build the difference between the current and the last value read from the data source. The value obtained is still divided by the elapsed time between the current and the last reading, which makes it dif ferent from the gauge option. Useful for external data gatherers. derive If you are using rrdtool as logger/grapher you can use a third type of data source. Derive is like counter, except that it is not required to go UP all the time. It is useful for situations where the change of some value should be graphed. unknaszero Log unknown data as zero instead of the default behaviour of repeating the last value seen. Be careful with this, often a flat line in the graph is much more obvious than a line at 0. withzeroes Normally we ignore all values which are zero when calculating the average transfer rate on a line. If this is not desirable use this option. noborder If you are using rateup to log data, MRTG will create the graph images. Normally these images have a shaded border around them. If you do not want the border to be drawn, enable this option. This option has no effect if you are not using rateup. noarrow As with the option above, this effects rateup graph generation only. Normally rateup will generate graphs with a small arrow show ing the direction of the data. If you do not want this arrow to be drawn, enable this option. This option has no effect if you are not using rateup. noi When using rateup for graph generation, you can use this option to stop rateup drawing a graph for the I or first variable. This also removes entries for this variable in the HTML page MRTG gener ates, and will remove the peaks for this variable if they are enabled. This allows you to hide this data, or can be very useful if you are only graphing one line of data rather than two. This option is not destructive - any data received for the the variable continued to be logged, it just isnt shown. noo Same as above, except relating to the O or second variable. nobanner When using rateup for graph generation, this option disables MRTG adding the MRTG banner to the HTML pages it generates. nolegend When using rateup for graph generation, this option will stop MRTG from creating a legend at the bottom of the HTML pages it gener ates. printrouter When using rateup for graph generation, this option will print the router name in the graph it generates. This option is overridden by the value of PNGTitle if one is given pngdate When using rateup for graph generation, this option will print a timestamp in the graph it generates, including a timezone if one is specified by the Timezone parameter. logscale The logscale option causes rateup to display the data with the Y axis scaled logarithmically. Doing so allows the normal traffic to occupy the majority of the vertical range, while still showing any spikes at their full height. logscale displays all the available data and will always produce well-behaved graphs. People often consider a logarithmically scaled graph counterintuitive, however, and thus hard to interpret. expscale The expscale option causes rateup to display the data with the Y axis scaled exponentially. Doing so emphasizes small changes at the top of the scale; this can be useful when graphing values that fluctuate by a small amount near the top of the scale, such as line voltage. expscale is essentially the inverse of logscale. secondmean The secondmean option sets the maximum value on the graph to the mean of the data greater than the mean of all data. This produces a graph that focuses more on the typical data, while clipping large peaks. Using secondmean will give a more intutive linearly scaled graph, but can result in a uselessly high or low scale in some rare situa tions (specifically, when the data includes a large portion of val ues far from the actual mean) If a target includes both logscale and secondmean in the options, the secondmean takes precedence. Example: Options[myrouter]: growright, bits kilo Use this option to change the multiplier value for building prefixes. Defaultvalue is 1000. This tag is for the special case that 1kB = 1024B, 1MB = 1024kB and so far. Example: kilo[myrouter]: 1024 kMG Change the default multiplier prefixes (,k,M,G,T,P). In the tag Short Legend define only the basic units. Format: Comma seperated list of prefixed. Two consecutive commas or a comma at start or end of the line gives no prefix on this item. If you do not want prefixes, just put two consecutive commas. If you want to skip a magnitude select - as value. Example: velocity in nm/s (nanometers per second) displayed in nm/h. ShortLegend[myrouter]: m/h kMG[myrouter]: n,u,m,,k,M,G,T,P options[myrouter]: perhour Colours The Colours tag allows you to override the default colour scheme. Note: All 4 of the required colours must be specified here. The colour name (Colourx below) is the legend name displayed, while the RGB value is the real colour used for the display, both on the graph and in the html doc. Format is: Col1#RRGGBB,Col2#RRGGBB,Col3#RRGGBB,Col4#RRGGBB Important: If you use the dorelpercent options tag a fifth colour name colour value pair is required: Col1#RRGGBB,Col2#RRGGBB,Col3#RRGGBB,Col4#RRGGBB,Col5#RRGGBB Colour1 First variable (normally Input) on default graph. Colour2 Second variable (normally Output) on default graph. Colour3 Max first variable (input). Colour4 Max second variable (output). RRGGBB 2 digit hex values for Red, Green and Blue. Example: Colours[myrouter]: GREEN#00eb0c,BLUE#1000ff,DARK GREEN#006600,VIOLET#ff00ff Background With the Background tag you can configure the background colour of the generated HTML page. Example: Background[myrouter]: #a0a0a0a YLegend, ShortLegend, Legend[1234] The following keywords allow you to override the text displayed for the various legends of the graph and in the HTML document: YLegend The Y-axis label of the graph. Note that a text which is too long to fit in the graph will be silently ignored. ShortLegend The units string (default b/s) used for Max, Average and Current Legend[1234IO] The strings for the colour legend. Example: YLegend[myrouter]: Bits per Second ShortLegend[myrouter]: b/s Legend1[myrouter]: Incoming Traffic in Bits per Second Legend2[myrouter]: Outgoing Traffic in Bits per Second Legend3[myrouter]: Maximal 5 Minute Incoming Traffic Legend4[myrouter]: Maximal 5 Minute Outgoing Traffic LegendI[myrouter]:  In: LegendO[myrouter]:  Out: Note, if LegendI or LegendO are set to an empty string with LegendO[myrouter]: The corresponding line below the graph will not be printed at all. Timezone If you live in an international world, you might want to generate the graphs in different timezones. This is set in the TZ variable. Under certain operating systems like Solaris, this will provoke the localtime call to give the time in the selected timezone. Example: Timezone[myrouter]: Japan The Timezone is the standard timezone of your system, ie Japan, Hongkong, GMT, GMT+1 etc etc. Weekformat By default, mrtg (actually rateup) uses the strftime(3) %V option to format week numbers in the monthly graphs. The exact semantics of this format option vary between systems. If you find that the week numbers are wrong, and your systems strftime(3) routine supports it, you can try another format option. The POSIX %V option correspond to the widely used ISO 8601 week numbering standard. The week format charac ter should be specified as a single letter; either W, V, or U. The UNIX version of rateup uses the libc implementation of strftime. On Windows, the native strftime implementation does not know about %V. So there we use a different implementation of strftime that does sup port %V. Example: Weekformat[myrouter]: W RRDRowCount This affects the creation of new rrd files. By default rrds are created to hold about 1 days worth of high resolution data. (plus 1 week of 30 minute data, 2 months of 2 hour data and 2 years of 1 day data). With this Keyword you can change the number of base interval entries config ured for new rrds as they get created. Note that you must take the interval time into account. Example: RRDRowCount[myrouter]: 1600 TimeStrPos This defines placement of the timestamp string on the image. Possible values are RU, LU, RL, LL (which stand, respectively, for RightUpper, LeftUpper, RightLower and LeftLower corner) and NO (for no timestamp). By default, no timestamp is placed on the image. Example: TimeStrPos[myrouter]: RU TimeStrFmt Using this keyword you may specify format of the timestamp to be placed on the image (if enabled by the TimeStrPos keyword). Specified string will be used by the strftime() function - see strftime(3) documentation for conversion specifiers available on your system. Default format: %Y-%m-%d %H:%M Example: TimeStrFmt[myrouter]: %H:%M:%S THRESHOLD CHECKING Through its threshold checking functionality mrtg is able to detect threshold problems for the various targets and can call external scripts to handle those problems (e.g. send email or a page to an administrator). Threshold checking is configured through the following parameters: ThreshDir (GLOBAL) By defining ThreshDir to point to a writable directory, MRTG will only alert you when a threshold boundery has been crossed. Example: ThreshDir: /var/mrtg/thresh ThreshMinI (PER TARGET) This is the minimum acceptable value for the Input (first) parameter. If the parameter falls below this value, the program specified in ThreshProgI will be run. If the value ends in % then the threshold is defined relative to MaxBytes. ThreshMaxI (PER TARGET) This is the maximum acceptable value for the Input (first) parameter. If the parameter falls above this value, the program specified in ThreshProgI will be run. If the value ends in % then the threshold is defined relative to MaxBytes. ThreshDesc (PER TARGET) Its value will be assigned to the environment variable THRESH_DESC before any of the programs mentioned below are called. The programms can use the value of this variable to produce more user-friendly out put. ThreshProgI (PER TARGET) This defines a program to be run if ThreshMinI or ThreshMaxI is broken. MRTG passes 3 arguments: the $router variable, the threshold value bro ken, and the current parameter value. ThreshProgOKI (PER TARGET) This defines a program to be run if the parameter is currently OK (based on ThreshMinI and ThreshMaxI), but wasnt OK on the previous running -- based on the files found in ThreshDir. MRTG passes 3 argu ments: the $router variable the unbroken threshold value, and the cur rent parameter value. ThreshMinO, ThreshMaxO, ThreshProgO, and ThreshProgOKO These work the same as their *I counterparts, except on the Output (second) parameter. Note that you can use the SetEnv parameter explained above to pass additional information to the threshold programs. SetEnv When calling threshold scripts from within your cfg file you might want to pass some data on to the script. This can be done with the SetEnv configuration option which takes a series of environment variable assignments. Note that the quotes are mandatory. This does not work for external scripts. It is not possible to set environment variables per target. Example: SetEnv[myrouter]: EMAIL="contact_email@someplace.net" HOST="www.some_server.net" PER TARGET DEFAULT VALUES Pre- and Postfix To save yourself some typing you can define a target called ^. The text of every Keyword you define for this target will be PREPENDED to the corresponding Keyword of all the targets defined below this line. The same goes for a Target called $ but its text will be APPENDED. Note that a space is inserted between the prepended text and the Key word value, as well as between the Keyword value and the appended text. This works well for text-valued Keywords, but is not very useful for other Keywords. See the "default" target description below. The example will make mrtg use a common header and a common contact person in all the pages generated from targets defined later in this file. Example: PageTop[^]:

NoWhere Unis Traffic Stats

PageTop[$]: Contact Peter Norton if you have any questions
To remove the prepend/append value, specify an empty value, e.g.: PageTop[^]: PageTop[$]: NoSpaceChar With PREPEND and APPEND (see below) there is normally a space inserted between the local value and the PRE- or APPEND value. Sometimes this is not desirable. You can use the global option NoSpaceChar to define a character which can be mentioned at the end of a $ or ^ definition in order to supress the space. Example: NoSpaceChar: ~ Target[^]: Target[a]: a.tolna.net Target[b]: b.tolna.net Target[c]: c.tolna.net Target[d]: d.tolna.net Default Values The target name _ specifies a default value for that Keyword. In the absence of explicit Keyword value, the prepended and the appended key word value, the default value will be used. Example: YSize[_]: 150 Options[_]: growright,bits,nopercent WithPeak[_]: ymw Suppress[_]: y MaxBytes[_]: 1250000 To remove the default value and return to the factory default, spec ify an empty value, e.g.: YLegend[_]: There can be several instances of setting the default/prepend/append values in the configuration file. The later setting replaces the previ ous one for the rest of the configuration file. The default/prepend/append values used for a given keyword/target pair are the ones that were in effect at the point in the configuration file where the target was mentioned for the first time. Example: MaxBytes[_]: 1250000 Target[myrouter.somplace.edu.2]: 2:public@myrouter.somplace.edu MaxBytes[_]: 8000 Title[myrouter.somplace.edu.2]: Traffic Analysis for myrouter.somplace.edu IF 2 The default MaxBytes for the target myrouter.someplace.edu.2 in the above example will be 1250000, which was in effect where the target name myrouter.someplace.edu.2 first appeared in the config file. COMMAND LINE OPTIONS --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 configura tion-file appended with "_l"). --confcache-file filename Use an alternate confcache-file (the default is to use the configu ration-file appended with ".ok") --logging filenameeventlog If this is set to writable filename, all output from mrtg (warn ings, debug messages, errors) will go to filename. If you are run ning 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 included with 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 you go to the mrtg contrib download area (on the website) you will find the mrtg-mes sage-dll.zip which does contain such a thing. --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 dae mon --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 coca - confcache operations fork - forking view time - some timing info log - logging of data via rateup or rrdtool eval - print eval strings before evaluting them Example: --debug="cfg,snpo" EXIT CODES An exit code of 0 indicates that all targets were successful. Gener ally speaking, most codes greater than 0 indicate that there was an unrecoverable problem. One exception to this is code 91, which indi cates that at least one of the targets was succesful. A partial list ing of the codes follows: 0: All targets sucessful 2: Config error (cant read, fatal error in config, etc) 17: Another MRTG process is processing config 91: At least one target sucessful 92: No targets were sucessful EXAMPLES Minimal mrtg.cfg WorkDir: /usr/tardis/pub/www/stats/mrtg Target[r1]: 2:public@myrouter.somplace.edu MaxBytes[r1]: 8000 Title[r1]: Traffic Analysis ISDN PageTop[r1]:

Stats for our ISDN Line

Cfg for several Routers. WorkDir: /usr/tardis/pub/www/stats/mrtg Title[^]: Traffic Analysis for PageTop[^]:

Stats for PageTop[$]: Contact The Chief if you notice anybody
MaxBytes[_]: 8000 Options[_]: growright Title[isdn]: our ISDN Line PageTop[isdn]: our ISDN Line

Target[isdn]: 2:public@router.somplace.edu Title[backb]: our Campus Backbone PageTop[backb]: our Campus Backbone Target[backb]: 1:public@router.somplace.edu MaxBytes[backb]: 1250000 # the following line removes the default prepend value # defined above Title[^]: Title[isdn2]: Traffic for the Backup ISDN Line PageTop[isdn2]: our ISDN Line Target[isdn2]: 3:public@router.somplace.edu AUTHOR Tobias Oetiker and many contributors 2.14.7 2006-09-06 MRTG-REFERENCE(1)

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