=head1 NAME

reference - MRTG 2.9.18 configuration reference

=head1 OVERVIEW

The runtime behaviour of MRTG is governed by a configuration file. Run of
the mill configuration files can be generated with B<cfgmaker>. (Check
L<cfgmaker>). But for more elaborate configurations some hand tuning is
required.

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

=head1 SYNTAX

MRTG configuration file syntax follows some simple rules:

=over

=item *

Keywords must start at the beginning of a line.

=item *

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

=item *

Empty Lines are ignored

=item *

Lines starting with a # sign are comments.

=item *

You can add other files into the configuration file using

B<Include:> I<file>

Example:

 Include: base-options.inc

=back

=head1 GLOBAL PARAMETERS

=head2 WorkDir

WorkDir specifies where the logfiles and the webpages should
be created.

Example:

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

=head1 OPTIONAL GLOBAL PARAMETERS

=head2 HtmlDir

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

NOTE: Workdir overides the settings for htmldir, imagedir
      and logdir

Example:

 Htmldir: /www/mrtg/

=head2 ImageDir

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

Example:

 Imagedir: /www/mrtg/images

=head2 LogDir

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

Example:

 Logdir: /www/mrtg/logs

=head2 Forks (UNIX only)

An a system that can 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.

Example:
 
 Forks: 4

=head2 Refresh

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 minutes).

Example:

 Refresh: 600

=head2 Interval

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:

=over

=item *

the generated HTML page does contain the right
information about the calling interval ...

=item *

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

=back

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

Example:

 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.


=head2 WriteExpires

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

Example:

 WriteExpires: Yes



=head2 NoMib2

Normally we ask the SNMP device for 'sysUptime', 'sysName' properties
some do not have these. If you want to avoid getting complaints from
mrtg about these missing properties, specivy 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 management
of a system.

Example:

 NoMib2: Yes

=head2 SingleRequest

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

Examples

 SingleRequest: Yes

=head2 SnmpOptions

Apart form 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 supported:

 timeout       	  	   => $default_timeout,
 retries 		   => $default_retries,
 backoff 		   => $default_backoff,
 default_max_repetitions   => $max_repetitions,
 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.

Example:

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.

=head2 IconDir

If you want to keep the mrtg icons in some place other than the
working (or imagedir) directory, use the I<IconDir> variable for
defining the url to the icons directory.

Example:

 IconDir: /mrtgicons/

=head2 LoadMIBs

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 WorkDir.

Example:

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

=head2 Language

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

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 
spanish 
swedish 
turkish 
ukrainian 

Example:

 Language: danish

=head2 LogFormat

Setting LogFormat to 'rrdtool' in your mrtg.cfg file enables rrdtool mode.
In rrdtool mode, mrtg relies on B<rrdtool> to do its logging. Graphs and html
pages will be generated on the fly by the 14all.cgi which can be found in
the contrib section together with a short readme ... This feature has been
contributed by S<Rainer Bawidamann E<lt>bawidama@users.sourceforge.netE<gt>>. Please check his
website for more information: http://www.wh-hms.uni-ulm.de/~widi/14all/

Example:

 LogFormat: rrdtool

=head2 LibAdd

If you are using rrdtool mode and your B<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.

Example:

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

=head2 PathAdd

If the B<rrdtool> executable can not be found in the normal C<PATH>, you can use
this parameter to add a suitable directory to your path.

Example:

 PathAdd: /usr/local/rrdtool/bin/

=head2 RunAsDaemon

The RunAsDaemon keyword enables daemon mode operation. The purpose of daemon
mode is that MRTG is launched once and not at regular basis by cron as in
native mode. This behavior saves computing resourses as loading and parsing
of configuration files only hapens 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 using daemon mode MRTG should no longer be started from cron by
regular basis as each started 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 B<--user=>I<user_name> and B<--group=>I<group_name>
options on the mrtg commandline.
 
 mrtg --user=mrtg_user --group=mrtg_group mrtg.cfg

Also note that in daemon mode restart of 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 the special start sequence when you launch the program:

 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.

Example

 RunAsDaemon:Yes
 Interval:5

Makes MRTG run as a daemon beginning data collection every 5 minutes

=head1 PER TARGET CONFIGURATION

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.

=head2 Target

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

=over

=item Basic

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.

Example:

 Target[ezwf]: 2:public@wellfleet-fddi.ethz.ch

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

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

=item SNMPv2c

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. As we now use 64 bit
instead of the normal 32 bit.

Example:

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


=item Reversing

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 traffic rates.

Example:

 Target[ezci]: -1:public@ezci-ether.ethz.ch

=item Explicit OIDs

You can also explicitly define the OID to query by using the
following 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 OID's such as temperature and humidity
or error input and error output.

Example:

 Target[ezwf]: 1.3.6.1.2.1.2.2.1.14.1&1.3.6.1.2.1.2.2.1.20.1:public@myrouter

=item MIB Variables

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

Example:

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

=item 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 wrong by offset, causing MRTG to graphs wrong instances etc.
MRTG supports IP address instead of ifindex in target definition. Then
MRTG will query snmp device and try to map IP address to current ifindex,
You can use IP address in every type of target definition, by adding
IP address of the numbered interface after OID and separation char '/'

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

You can tell cfgmaker to generate such references with the option
B<--ifref=ip>.

Example:

 Target[ezwf]: /1.2.3.4:public@wellfleet-fddi.ethz.ch
 Target[ezci]: -/1.2.3.4:public@ezci-ether.ethz.ch
 Target[ezwf]: 1.3.6.1.2.1.2.2.1.14/1.2.3.4&1.3.6.1.2.1.2.2.1.14/1.2.3.4:public@myrouter
 Target[ezwf]: ifInErrors/1.2.3.4&ifOutErrors/1.2.3.4:public@myrouter

=item 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
only that the prefix to use is a \ instead of a /

You can tell cfgmaker to generate such references with the option
B<--ifref=descr>.

Example:

 Target[ezwf]: \My-Interface2:public@wellfleet-fddi.ethz.ch
 Target[ezci]: -\My-Interface2:public@ezci-ether.ethz.ch
 Target[ezwf]: 1.3.6.1.2.1.2.2.1.14\My-Interface2&1.3.6.1.2.1.2.2.1.14\My-Interface3:public@myrouter
 Target[ezwf]: 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[ezwf]: \fun\: \ ney\&ddd:public@hello.router

=item Interface by Name

The only sensible way to reference interfaces of your switches.

You can tell cfgmaker to generate such references with the option
B<--ifref=name>.

Example:

 Target[ezwf]: #2/11:public@wellfleet-fddi.ethz.ch
 Target[ezci]: -#2/11:public@ezci-ether.ethz.ch
 Target[ezwf]: 1.3.6.1.2.1.2.2.1.14#3/7&1.3.6.1.2.1.2.2.1.14#3/7:public@myrouter
 Target[ezwf]: 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[ezwf]: #\: \ fun:public@hello.router

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

=item 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 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 their Interface 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 B<--ifref=eth>.

Example:

 Target[ezwf]: !0a-0b-0c-0d:public@wellfleet-fddi.ethz.ch
 Target[ezci]: -!0-f-bb-05-71-22:public@ezci-ether.ethz.ch
 Target[ezwf]: 1.3.6.1.2.1.2.2.1.14!0a-00-10-23-44-51&!0a-00-10-23-44-51:public@myrouter
 Target[ezwf]: ifInErrors!0a-00-10-23-44-51&ifOutErrors!0a-00-10-23-44-51:public@myrouter


=item Interface by Type

It seems that there are devices that try to defy all monitoring efforts, the interesting interfaces have
neither ifName nor a constant ifDescr not to think of 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
B<--ifref=type>.

Example:

 Target[ezwf]: %13:public@wellfleet-fddi.ethz.ch
 Target[ezci]: -%13:public@ezci-ether.ethz.ch
 Target[ezwf]: 1.3.6.1.2.1.2.2.1.14%13&1.3.6.1.2.1.2.2.1.14%14:public@myrouter
 Target[ezwf]: ifInErrors%13&ifOutErrors%14:public@myrouter

=item Extended Host Name Syntax

In all places where ``community@router'' is accepted, you can add
additional parameters for the SNMP communication using
colon-separated suffixes. The full syntax is as follows:

 community@router[:[port][:[timeout][:[retries][:[backoff][:version]]]]]

where the meaning of each parameter is as follows:

=over

=item port

the UDP port under which to contact the SNMP agent (default: 161)

=item timeout

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

=item retries

number of times a timed-out request will be retried (default: 5)

=item backoff

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

=item version

for SNMP version if you have a fast router you might want to put
a '2' here. This will make mrtg try to poll the 64 bit counters. And thus
prevent excessive counter wrapping. Not all routers support this though.

Example:

 3:public@router1:::::2

=back

A value that equals the default value can be omitted.  Trailing colons
can be omitted, too.

Example:

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

This would refer to the input/output octet counters for the interface
with I<ifIndex 1> on I<ezci-ether.ethz.ch>, 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.

=item 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:

=over 4

=item Line 1

current state of the first variable, normally 'incoming bytes count'

=item Line 2

current state of the second variable, normally 'outgoing bytes count'


=item Line 3

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

=item Line 4

string, telling the name of the target.

=back

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

Example:

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

Note the use of the backticks (`), not apostrophes (')
around the command.

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



=item Multi Target Syntax

You can also use several statements in a mathematical
expression.  This could be used to aggregate both B channels
in an ISDN connection or multiple T1s that are aggregated
into a single channel for greater bandwidth.
Note the whitespace arround the target definitions.

Example:

 Target[ezwf]: 2:public@wellfleetA + 1:public@wellfleetA
              * 4:public@ciscoF

=back

=head2 RouterUptime

In cases where you calculate the used bandwidth from
several interfaces you normaly don't 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 nevertheless you have to specify
its community and address again with the I<RouterUptime> keyword.


Example:

 Target[kacisco.comp.edu]: 1:public@194.64.66.250 + 2:public@194.64.66.250
 RouterUptime[kacisco.comp.edu]: public@194.64.66.250


=head2 MaxBytes

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

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

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 second.  This is very important to make your
unscaled graphs display realistic information.
T1 = 193000, 56K = 7000, Ethernet = 1250000. The I<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
variables, you can use MaxBytes1 and MaxBytes2 instead of MaxBytes.

Example:

 MaxBytes[ezwf]: 1250000

=head2 MaxBytes1

Same as MaxBytes, for variable 1.

=head2 MaxBytes2

Same as MaxBytes, for variable 2.

=head2 Title

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

Example:

 Title[ezwf]: Traffic Analysis for Our Nice Company

=head2 PageTop

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.

Example:

 PageTop[ezwf]: <H1>Traffic Analysis for ETZ C95.1</H1>
   Our Campus Backbone runs over an FDDI line\n
   with a maximum transfer rate of 12.5 megabytes per
   Second.


=head1 OPTIONAL PER TARGET PARAMETERS

=head2 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 E<lt>/BODYE<gt> tag:

Example:

 PageFoot[ezwf]: Contact <A HREF="mailto:peter@x.yz">Peter</A>
  if you have questions regarding this page

=head2 AddHead

Use this tag like the I<PageTop> header, but its contents
will be added between E<lt>/TITLEE<gt> and E<lt>/HEADE<gt>.

Example:

 AddHead[ezwf]: <link rev="made" href="mailto:mrtg@blabla.edu">

=head2 BodyTag

BodyTag lets you supply your very own E<lt>body ...E<gt> tag for the
generated webpages.

Example:

 BodyTag[ezwf]: <BODY LEFTMARGIN="1" TOPMARGIN="1" 
                      BACKGROUND="/stats/images/bg.neo2.gif">

=head2 AbsMax

If you are monitoring a link which can handle more traffic
than the I<MaxBytes> value. Eg, a line which uses compression
or some frame relay link, you can use the I<AbsMax> keyword
to give the absolute maximum value ever to be reached.
We need to know this in order to sort out unrealistic values
returned by the routers. If you do not set I<AbsMax>, rateup
will ignore values higher than I<MaxBytes>.

Example:

 AbsMax[ezwf]: 2500000

=head2 Unscaled

By default each graph is scaled vertically to make the
actual data visible even when it is much lower than
I<MaxBytes>.  With the I<Unscaled> variable you can suppress
this.  It's argument is a string, containing one letter
for each graph you don't want to be scaled: d=day w=week
m=month y=year.  In the example scaling for the
yearly and the monthly graph are suppressed.

Example:

 Unscaled[ezwf]: ym

=head2 WithPeak

By default the graphs only contain the average
values of the monitored variables - normally the
transfer rates for incoming and outgoing traffic.
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[ezwf]: ym

=head2 Suppress

By default mrtg produces 4 graphs. With this option
you can suppress the generation of selected graphs.
The option value syntax is analogous to the above two options.
In this example we suppress the yearly graph
as it is quite empty in the beginning.

Example:

 Suppress[ezwf]: y

=head2 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 (usefull
for getting a router name out of a database).

Example:

 Extension[ezwf]: phtml

=head2 Directory

By default, mrtg puts all the files that it generates for each
target (the GIFs, the HTML page, the log file, etc.) in I<WorkDir>.

If the I<Directory> option is specified, the files are instead put
into a directory under I<WorkDir> or Log-, Image- and HtmlDir).
(For example the I<Directory>
option below would cause all the files for a target ezwf
to be put into directory /usr/tardis/pub/www/stats/mrtg/ezwf/ .)

The directory must already exist; mrtg will not create it.

Example:

 WorkDir: /usr/tardis/pub/www/stats/mrtg
 Directory[ezwf]: ezwf

NOTE: the Directory option must always be 'relative' or bad things will happen.

=head2 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[ezwf]: 300
 YSize[ezwf]: 300

=head2 XZoom and YZoom

If you want your graphs to have larger pixels, you can
"Zoom" them.

Example:

 XZoom[ezwf]: 2.0
 YZoom[ezwf]: 2.0

=head2 XScale and YScale

If you want your graphs to be actually scaled use I<XScale>
and I<YScale>. (Beware while this works, the results look ugly
(to be frank) so if someone wants to fix this: patches are welcome.

Example:

 XScale[ezwf]: 1.5
 YScale[ezwf]: 1.5


=head2 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 YTicsFactor.
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[ezwf]: 7
  YTicsFactor[ezwf]: 0.01

=head2 Factor

If you want to multiply all numbers shown below the graph with a constant factor, use
this directive to define it ..

Example:

  Factor[as400]: 4096

=head2 Step

Change the default step from 5 * 60 seconds to
something else (I have not tested this well ...)

Example:

 Step[ezwf]: 60

=head2 Options

The I<Options> Keyword allows you to set some boolean
switches:

=over

=item 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.

=item 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.

=item 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.

=item 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.

=item noinfo

Suppress the information about uptime and
device name in the generated webpage.

=item nopercent

Don't print usage percentages

=item transparent

make the background of the generated gifs transparent ...

=item integer

Print summary lines below graph as integers without comma

=item 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
for IN-traffic greater than OUT-traffic also 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 I<Colours>
options, a fifth colour-name colour-value pair is required there.

=item 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 avarage 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? Though so!)

=item gauge

Treat the values gathered from target as 'current status' measurements
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 variable as a counter and calculates
the difference between the current and the previous value
and divides that by the elapsed time between
the last two readings to get the value to be plotted.

=item 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 different from the 'gauge' option. Useful for external data gatherers.

=item 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.

=item 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.

=item 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.

=item noarrow

As with the option above, this effects rateup graph generation only. Normally
rateup will generate graphs with a small arrow showing 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.

=item 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 generates, 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 isn't shown.

=item noo

Same as above, except relating to the 'O' or second variable.

=item nobanner

When using rateup for graph generation, this option disables MRTG adding the
MRTG banner to the HTML pages it generates.

=item nolegend

When using rateup for graph generation, this option will stop MRTG creating
a legend at the bottom of the HTML pages it generates.

=back

Example:

 Options[ezwf]: growright, bits


=head2 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[ezwf]: 1024


=head2 kMG

Change the default multiplier prefixes (,k,M,G,T,P). In the tag
I<ShortLegend> 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.
Note: If you do not want prefixes, then leave this line blank.

Example: velocity in nm/s (nanometers per second) displayed in nm/h.

 ShortLegend[ezwf]: m/h
 kMG[ezwf]: n,u,m,,k,M,G,T,P
 options[ezwf]: perhour


=head2 Colours

The I<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 I<dorelpercent> options tag a fifth colour name
colour value pair is required:
Col1#RRGGBB,Col2#RRGGBB,Col3#RRGGBB,Col4#RRGGBB,Col5#RRGGBB

=over 4

=item Colour1

First variable (normally Input) on default graph

=item Colour2

Second variable (normally Output) on default graph

=item Colour3

Max first variable (input)

=item Colour4

Max second variable (output)

=item RRGGBB

2 digit hex values for Red, Green and Blue

=back

Example:

 Colours[ezwf]: GREEN#00eb0c,BLUE#1000ff,DARK GREEN#006600,VIOLET#ff00ff

=head2 Background

With the I<Background> tag you can configure the background
colour of the generated HTML page

Example:

 Background[ezwf]: #a0a0a0a

=head2 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

=over 4

=item 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.

=item ShortLegend

The units string (default 'b/s') used for Max, Average and Current

=item Legend[1234IO]

The strings for the colour legend

=back

Example:

  YLegend[ezwf]: Bits per Second
  ShortLegend[ezwf]: b/s
  Legend1[ezwf]: Incoming Traffic in Bits per Second
  Legend2[ezwf]: Outgoing Traffic in Bits per Second
  Legend3[ezwf]: Maximal 5 Minute Incoming Traffic
  Legend4[ezwf]: Maximal 5 Minute Outgoing Traffic
  LegendI[ezwf]: &nbsp;In:
  LegendO[ezwf]: &nbsp;Out:

Note, if I<LegendI> or I<LegendO> are set to an empty string with

 LegendO[ezwf]:

The corresponding line below the graph will not be printed at all.

=head2 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[ezwf]: Japan

The Timezone is the standard Solaris timezone, ie Japan, Hongkong,
GMT, GMT+1 etc etc.

=head2 Weekformat

By default, mrtg (actually rateup) uses the strftime(3) '%W' 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 system's strftime(3) routine
supports it, you can try another format option.  The POSIX '%V'
option seems to correspond to a widely used week numbering
convention.  The week format character should be specified as a
single letter; either W, V, or U.

Example:

 Weekformat[ezwf]: V



=head1 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 (send email or a page to an administrator).

Threshold checking is configured through the following parameters:

=head2 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

=head2 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.

=head2 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.

=head2 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 userfriendly output.

=head2 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
broken, and the current parameter value.

=head2 ThreshProgOKI  (PER TARGET)

This defines a program to be run if the parameter is currently OK (based on
ThreshMinI and ThreshMaxI), but wasn't OK on the previous running -- based
on the files found in ThreshDir. MRTG passes 3 arguments: the $router
variable the un-broken threshold value, and the current parameter value.

=head2 ThreshMinO, ThreshMaxO, ThreshProgO, and ThreshProgOKO

They work the same as their *I counterparts, except on the Output (second)
parameter.

I<Note, that you can use the SetEnv parameter explained above to pass
additional information to the threshold programs.>

=head2 SetEnv

When calling threshol 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 ... it takes a series of environment variable
assignments. Note that the quotes are mandatory. Note that this does not
work for external scripts because of the way mrtg evaluates them it is not
possible to set environment variables per target.

Example:

 SetEnv[myrouter]:  EMAIL="contact_email@someplace.net"
                    HOST="www.some_server.net"
                    URL="http://www.some_server.net/path/mrtg.html"

=head1 PER TARGET DEFAULT VALUES

=head2 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 Keyword 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[^]: <H1>NoWhere Unis Traffic Stats</H1><HR>
 PageTop[$]: Contact Peter Norton if you have any questions<HR>

To remove the prepend/append value, specify an empty value, e.g.:

 PageTop[^]:
 PageTop[$]:

NOTE: With PREPEND and APPEND 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 I<NoSpaceChar> config option to define a character which can be
mentioned at the end of a $ or ^ definition in order to supress the space.

Example:

  NoSpaceChar: ~
  Target[^]: 1.3.6.1.4.1.482.50.2.4.20.0&1.3.6.1.4.1.482.50.2.4.21.0:get@~
  Target[a]: a.tolna.net
  Target[b]: b.tolna.net
  Target[c]: c.tolna.net
  Target[d]: d.tolna.net

=head2 Default Values

The target name '_' specifies a default value for that
Keyword. In the absence of explicit Keyword value, the prepended
and the appended keyword 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',
specify 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
previous 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 I<MaxBytes> for the target myrouter.somplace.edu.2
in the above example will be 1250000, which was in effect
where the target name myrouter.somplace.edu.2 first appeared
in the config file.

=head1 COMMAND LINE OPTIONS

=over

=item B<--user> I<username>  and B<--group> I<groupname>

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

=item B<--lock-file> I<filename>

Use an alternate lock-file (the default is to use the configuration-file
appended with C<_l>).

=item B<--confcache-file> I<filename>

Use an alternate confcache-file (the default is to use the configuration-file appended with C<.ok>)

=item B<--logging> I<filename>|B<eventlog>

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

B<NOTE:>Note, there is no Message DLL for mrtg which 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.

=head1 EXAMPLES


=head2 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]: <H1>Stats for our ISDN Line</H1>


=head2 Cfg for several Routers.

 WorkDir: /usr/tardis/pub/www/stats/mrtg
 Title[^]: Traffic Analysis for
 PageTop[^]: <H1>Stats for
 PageTop[$]: Contact The Chief if you notice anybody<HR>
 MaxBytes[_]: 8000
 Options[_]: growright

 Title[isdn]: our ISDN Line
 PageTop[isdn]: our ISDN Line</H1>
 Target[isdn]: 2:public@router.somplace.edu

 Title[backb]: our Campus Backbone
 PageTop[backb]: our Campus Backbone</H1>
 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</H1>
 Target[isdn2]: 3:public@router.somplace.edu

=head1 AUTHOR

Tobias Oetiker E<lt>oetiker@ee.ethz.chE<gt> and many contributors
