| MRTG-REFERENCE(1) | mrtg | MRTG-REFERENCE(1) |
mrtg-reference - MRTG 2.17.10 configuration reference
The runtime behaviour of MRTG is governed by a configuration file. Run-of-the-mill configuration files can be generated with cfgmaker. (Check cfgmaker). But for more elaborate configurations some hand-tuning is required.
This document describes all the configuration options understood by the mrtg software.
MRTG configuration file syntax follows some simple rules:
Include: file
Example:
Include: base-options.inc
If included files are specified with relative paths, both the current working directory and the directory containing the main config file will be searched for the files. The current working directory will be searched first.
If the included filename contains an asterisk, then this is taken as a wildcard for zero or more characters, and all matching files are included. Thus, you can use this statement to include all files in a specified subdirectory.
Example:
Include: servers/*.cfg
In this case, you should be very careful that your wildcard pattern does not find a match relative to the current working directory if you mean it to be relative to the main config file directory, since the working directory is checked for a match first (as with a normal Include directive). Therefore, use of something like '*/*' is discouraged.
WorkDir specifies where the logfiles and the webpages should be created.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
HtmlDir specifies the directory where the html (or shtml, but we'll get on to those later) lives.
NOTE: Workdir overrides the settings for htmldir, imagedir and logdir.
Example:
Htmldir: /www/mrtg/
ImageDir specifies the directory where the images live. They should be under the html directory.
Example:
Imagedir: /www/mrtg/images
LogDir specifies the directory where the logs are stored. This need not be under htmldir directive.
Example:
Logdir: /www/mrtg/logs
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.
Example:
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.
Example:
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.
Example:
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 minutes).
Example:
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:
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 in the format
Interval: MM[:SS]
Down to 1 second. 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. Also note that you must make sure that your mrtg-rrd Web-frontend can deal with this kind of Interval setting.
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 cause.
Example:
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
Example:
WriteExpires: Yes
Normally we ask the SNMP device for 'sysUptime' and 'sysName' properties. 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 management of a system.
Example:
NoMib2: Yes
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
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 supported:
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 implementation of SMC Barricade routers.
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.
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.
Example:
IconDir: /mrtgicons/
Load the MIB file(s) specified and make its OIDs available as symbolic names. For better efficiency, a cache of MIBs is maintained in the WorkDir.
Example:
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 translations).
Currently the following languages 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
Setting LogFormat to 'rrdtool' in your mrtg.cfg file enables rrdtool mode. In rrdtool mode, mrtg relies on rrdtool to do its logging. See mrtg-rrd.
Example:
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.
Example:
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.
Example:
PathAdd: /usr/local/rrdtool/bin/
If you are running RRDTool 1.4 or later with rrdcached, then you can configure MRTG to take advantage of this for updates, either by using the RRDCACHED_ADDRESS environment variable, or by setting the RRDCached keyword in the configuration file. Note that, if both are set, the configuration file keyword will take precedence.
Only UNIX domain sockets are fully supported prior to RRDTool v1.5, and you should note that using RRDCached mode will disable all Threshold checking normally done by MRTG. Appropriate warning messages will be printed if necessary.
Examples:
RRDCached: unix:/var/tmp/rrdcached.sock RRDCached: localhost:42217
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 resources as loading and parsing of configuration files happens only once on startup, and if the configuration file is modified.
Using daemon mode MRTG itself is responsible for timing the measurement intervals. Therefore its important to set the Interval keyword to an appropriate 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 recommended 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 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
This makes MRTG run as a daemon beginning data collection every 5 minutes
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.
If the modification date on the configuration file changes during operation, then MRTG will re-read the configuration on the next polling cycle. Note that sub-files which are included from the main configuration do not have their modification times monitored, only the top-level file is so checked.
Some devices may produce non-numeric values that would nevertheless be useful to graph with MRTG if those values could be converted to numbers. The ConversionCode keyword specifies the path to a file containing 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 subroutine must return an undefined value if the conversion fails. In case of failure, a warning may be posted to the MRTG log file using Perl's warn function. MRTG imports the subroutines into a separate name space (package MRTGConversion), so the user need not worry about pollution of MRTG's global name space. MRTG automatically prepends this package declaration 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 arbitrarily 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 follows:
Target[myrouter]: 1.3.6.1.4.1.999.1&1.3.6.1.4.1.999.1:public@mydevice|Length2Int
See "Extended Host Name Syntax" below for complete target definition syntax information.
If you want to send a copy of the collected data into a Graphite database in addition to storing it in the RRDfile, you can provide your Graphite database name/ip and port number here.
This requires the Net::Graphite perl module which is available from CPAN.
Examples:
# If your Graphite receiver is running on the same host as the MRTG daemon and using the default port SendToGraphite: 127.0.0.1,2003 # If your Graphite receiver is running on 192.168.100.50 port 5000 SendToGraphite: 192.168.100.50,5000 # If your Graphite receiver is running on graphite.mydomain.com port 2003 SendToGraphite: graphite.mydomain.com,2003
Graphite's namespace has a number of restrictions on what characters are allowed. The SendToGraphite functionality makes an attempt to convert the MRTG target name and, if specified, the Legendi and Legendo values to Graphite namespace friendly values. Specifically, the following conversion rules apply:
Example MRTG target to Graphite namespace conversion:
# Our MRTG target name from mrtg.cfg is as follows Target[switch_GigabitEthernet0_5]: \GigabitEthernet0/5:public1@switch:::::2
After the conversion you will end up with these Graphite namespace values
m2g.switch.gigabitethernet0.5.in m2g.switch.gigabitethernet0.5.out
Next is a more complicated example because Legendi and Legendo are in use to denote min and max voltage values that pertain to some APC UPS SNMP OIDs
# Target, Legendi, and Legendo are specified in mrtg.cfg as follows Target[apc_minmaxline]: 1.3.6.1.4.1.318.1.1.1.3.2.3.0&1.3.6.1.4.1.318.1.1.1.3.2.2.0:public@apc: LegendI[apc_minmaxline]: upsAdvInputMinLineVoltage LegendO[apc_minmaxline]: upsAdvInputMaxLineVoltage
After the conversion you will end up with these Graphite namespace values
m2g.apc.minmaxline.upsAdvInputMinLineVoltage m2g.apc.minmaxline.upsAdvInputMaxLineVoltage
If you don't see the data showing up in Graphite, chances are there are invalid characters in the namespace. To debug this, use the DEBUG=qw(log) directive at the top of the MRTG script to find out what is happening with the MRTG to Graphite namespace conversion.
DEBUG=qw(log) will generate some output similar to what appears below
2016-10-13 06:08:39 -- --log: RRDs::update(/var/www/mrtg/switch/switch_gigabitethernet0_5.rrd, '1476356919:2738746035:2927936327') 2016-10-13 06:08:39 -- --log: graphite->send(m2g.switch.gigabitethernet0.5.in,2738746035,1476356919) 2016-10-13 06:08:39 -- --log: graphite->send(m2g.switch.gigabitethernet0.5.out,2927936327,1476356919) 2016-10-13 06:09:25 -- --log: RRDs::update(/var/www/mrtg/apc/apc_minmaxline.rrd, '1476356965:122:123') 2016-10-13 06:09:25 -- --log: graphite->send(m2g.apc.minmaxline.upsAdvInputMinLineVoltage,122,1476356965) 2016-10-13 06:09:25 -- --log: graphite->send(m2g.apc.minmaxline.upsAdvInputMaxLineVoltage,123,1476356965)
If the MRTG log output looks reasonable, then take a look at Graphite's carbon-cache logs.
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 Target keyword takes arguments in a wide range of formats:
Example:
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
Example:
Target[myrouter]: 2:public@router1:::::2
SNMP v3 requires additional authentication parameters, passed using the SnmpOptions[] per-target keyword.
Example:
Target[myrouter]: 2:router1:::::3
SnmpOptions[myrouter]: username=>'user1'
Example:
Target[myrouter]: #Bri0:router1:::::3
SnmpOptions[myrouter]: username=>'user1'
noHC[myrouter]: yes
Example:
Target[ezci]: -1:public@ezci-ether.domain
Example:
Target[myrouter]: 1.3.6.1.2.1.2.2.1.14.1&1.3.6.1.2.1.2.2.1.20.1:public@myrouter
Example:
Target[myrouter]: ifInErrors.1&ifOutErrors.1:public@myrouter
Example:
Target[myrouter]: WaLKstrangeOid.1&WaLKstrangeOid.2:public@myrouter
Target[myrouter]: WaLK3strangeOid.1&WaLK4strangeOid.2:public@myrouter
Example:
Target[myrouter]: GeTNEXTstrangeOid&GeTNEXTstrangeOid:public@myrouter
Example:
Target[myrouter]: CnTWaLK1.3.6.1.4.1.9.10.55.1.1.1.1.3&CnTWaLK1.3.6.1.4.1.9.10.55.1.1.1.1.3:public@myrouter
Make sure that the given IP address is used on 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 --ifref=ip.
Example:
Target[myrouter]: /1.2.3.4:public@wellfleet-fddi.domain
Target[ezci]: -/1.2.3.4:public@ezci-ether.domain
Target[myrouter]: ifInErrors/1.2.3.4&ifOutErrors/1.2.3.4:public@myrouter
You can tell cfgmaker to generate such references with the option --ifref=descr.
Example:
Target[myrouter]: \My-Interface2:public@wellfleet-fddi.domain
Target[ezci]: -\My-Interface2:public@ezci-ether.domain
Target[myrouter]: ifInErrors\My-If2&ifOutErrors\My-If3: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
You can tell cfgmaker to generate such references with the option --ifref=name.
Example:
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.
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.
Example:
Target[myrouter]: !0a-0b-0c-0d:public@wellfleet-fddi.domain
Target[ezci]: -!0-f-bb-05-71-22:public@ezci-ether.domain
Target[myrouter]: 1.3.6.1.2.1.2.2.1.14!0a-00-10-23-44-51& *BREAK*
1.3.6.1.2.1.2.2.1.14!0a-00-10-23-44-51:public@myrouter
Target[myrouter]: ifInErrors!0a-00-10-23-44-51& *BREAK*
ifOutErrors!0a-00-10-23-44-51:public@myrouter
Join the lines at *BREAK* ...
You can tell cfgmaker to generate such references with the option --ifref=type.
Example:
Target[myrouter]: %13:public@wellfleet-fddi.domain
Target[ezci]: -%13:public@ezci-ether.domain
Target[myrouter]: ifInErrors%13&ifOutErrors%14:public@myrouter
Example:
Target[myrouter]: OID.IndexPOS.1/1.2.3.4&OID.IndexPOS.1/1.2.3.4:public@myrouter
Replace OID by your numeric OID.
community@router[:[port][:[timeout][:[retries][:[backoff][:[version]]]]][|name]
where the meaning of each parameter is as follows:
The complete syntax of the port parameter is
remote_port[!local_address[!local_port]]
Some machines have additional security features that only allow SNMP queries to come from certain IP addresses. If the host doing the query has multiple interface, it may be necessary to specify the interface the query should come from.
The port parameter allows the specification of the port of the machine being queried. In addition, the IP address (or hostname) and port of the machine doing the query may be specified.
Examples:
somehost
somehost:161
somehost:161!192.168.2.4!4000 use 192.168.2.4 and port 4000 as source
somehost:!192.168.2.4 use 192.168.2.4 as source
somehost:!!4000 use port 4000 as source
Example:
3:public@router1:::::2
Example:
1.3.6.1.4.1.999.1&1.3.6.1.4.1.999.2:public@mydevice:161::::2|Length2Int
This would retrieve values from the OID 1.3.6.1.4.1.999.1 for input and .2 for output on mydevice using UDP port 161 and SNMP version 2, and would execute the user-defined numeric conversion 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.
Example:
Target[ezci]: 1:public@ezci-ether.domain:9161::4
This would refer to the input/output octet counters for the interface 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.
Example:
Target[IPv6test]: 2:public@[2001:760:4::]:6161::4
The external command must return 4 lines of output:
Depending on the type of data your script returns you might want to use the 'gauge' or 'absolute' arguments for the Options keyword.
Example:
Target[myrouter]: `/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 ...
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 really equipped to handle unknown data well.
Examples:
Target[myrouter]: 2:public@wellfleetA + 1:public@wellfleetA
Target[myrouter]: .1.3.6.1.4.1.999.1&.1.3.6.1.4.1.999.2:public@mydevice /
.1.3.6.1.4.1.999.3&.1.3.6.1.4.1.999.4:public@mydevice * 100
Note that whitespace must surround each target definition in the expression. Target definitions themselves must not contain whitespace, 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 integer unless RRDTool logging is in use and the gauge option is in effect for the target. Internally MRTG uses Perl's 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.
Example:
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:public@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 1:public@CiscoA.
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 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, 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 variables, you can use MaxBytes1 and MaxBytes2 instead of MaxBytes.
Example:
MaxBytes[myrouter]: 1250000
Title for the HTML page which gets generated for the graph.
Example:
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.
Example:
PageTop[myrouter]: <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.
In cases where you calculate the used bandwidth from several interfaces you normally 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 you have to specify its community and address again with the RouterUptime keyword.
If you want to use a special OID for querying the router uptime, use prepend the oid.
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 RouterUptime[kacisco.comp.edu]: hrSystemUptime.0:public@194.64.66.250
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 different 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 1.3.6.1.4.1.4779.1.1.3.0, so we can have MRTG display this instead of sysName.
Example:
RouterName[kacisco.comp.edu]: 1.3.6.1.4.1.4779.1.1.3.0
A different OID on a different host can also be specified:
RouterName[kacisco.comp.edu]: 1.3.6.1.4.1.4779.1.1.3.0:public@194.64.66.251
Same as MaxBytes, for variable 1.
Same as MaxBytes, for variable 2.
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
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.
Example:
SnmpOptions[myrouter]: username=>'user1'
Example:
SnmpOptions[myrouter]: username=>'user1',authpassword=>'example',
contextengineid=>'80000001110000004000000'
Example:
SnmpOptions[myrouter]:
authkey=>'0x1e93ab5a396e2af234c8920e61cfe2028072c0e2',
authprotocol=>'sha',privprotocol=>'des',username=>'user1',
privkey=>'0x498d74940c5872ed387201d74b9b25e2'
snmp options
The following option keywords are recognized:
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 </BODY> tag:
Example:
PageFoot[myrouter]: Contact <A HREF="mailto:peter@x.yz">Peter</A> if you have questions regarding this page
Use this tag like the PageTop header, but its contents will be added between </TITLE> and </HEAD>.
Example:
AddHead[myrouter]: <link rev="made" href="mailto:mrtg@blabla.edu">
BodyTag lets you supply your very own <body ...> tag for the generated webpages.
Example:
BodyTag[myrouter]: <BODY LEFTMARGIN="1" TOPMARGIN="1"
BACKGROUND="/stats/images/bg.neo2.gif">
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 unrealistic values returned by the routers. If you do not set AbsMax, rateup will ignore values higher than MaxBytes.
Example:
AbsMax[myrouter]: 2500000
By default each graph is scaled vertically to make the actual data visible even when it is much lower than MaxBytes. With the 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. 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
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[myrouter]: ym
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[myrouter]: y
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
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.
If the Directory option is specified, the Clonedirectory option will copy all the contents of Directory to the Clonedirectory.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg Directory[myrouter]: myrouter Clonedirectory[myrouter]: myclonedirectory
Optionally the target name can be changed in the cloning process.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg Directory[myrouter]: myrouter Clonedirectory[myrouter]: myclonedirectory mynewtarget
NOTE1: The clone directory must already exist; mrtg will not create it.
NOTE2: The Clonedirectory option must also always be 'relative' or bad things will happen.
NOTE3: This requires the File::Copy module
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
If you want your graphs to have larger pixels, you can "Zoom" them.
Example:
XZoom[myrouter]: 2.0 YZoom[myrouter]: 2.0
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
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[myrouter]: 7 YTicsFactor[myrouter]: 0.01
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
Change the default step from 5 * 60 seconds to something else (I have not tested this much ...)
Example:
Step[myrouter]: 60
When using rateup for graph generation, this will print the given title in the graph it generates.
Example:
PNGTitle[myrouter]: WAN Link UK-US
The Options Keyword allows you to set some boolean switches:
In the absence of 'gauge' or 'absolute' options, MRTG treats variables as a counters 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.
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 is essentially the inverse of logscale.
Using secondmean will give a more intuitive linearly scaled graph, but can result in a uselessly high or low scale in some rare situations (specifically, when the data includes a large portion of values 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
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
Change the default multiplier prefixes (,k,M,G,T,P). In the tag ShortLegend define only the basic units. Format: Comma separated 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
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
Example:
Colours[myrouter]: GREEN#00eb0c,BLUE#1000ff,DARK GREEN#006600,VIOLET#ff00ff
With the Background tag you can configure the background colour of the generated HTML page.
Example:
Background[myrouter]: #a0a0a0a
With the TextColor tag you can configure the text colour of the generated HTML page.
Example:
TextColor[myrouter]: #a0a0a0a
The following keywords allow you to override the text displayed for the various legends of the graph and in the HTML document:
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.
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.
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 system's 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 character 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 support %V.
Example:
Weekformat[myrouter]: W
This affects the creation of new rrd files. By default rrds are created to hold about 1 day's 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 configured for new rrds as they get created. Note that you must take the interval time into account.
Example:
RRDRowCount[myrouter]: 1600
As per RRDRowCount, but for the RRA's -typically- used for 30 minute data. Even so, you must still take the base interval into account. Leaving out this keyword will force the old default of 800 rows.
Example:
RRDRowCount30m[myrouter]: 800
As per RRDRowCount, but for the RRA's -typically- used for 2 hour data. Even so, you must still take the base interval into account. Leaving out this keyword will force the old default of 800 rows.
Example:
RRDRowCount2h[myrouter]: 400
As per RRDRowCount, but for the RRA's -typically- used for 1 day data. Even so, you must still take the base interval into account. Leaving out this keyword will force the old default of 800 rows.
Example:
RRDRowCount1d[myrouter]: 200
Normally the RRDs created by MRTG will just contain the information gathered directly from the respective target. With this option you can tap into rrdtools advanced aberrant behaviour detection module based on Holt-Winters forecasting. The RRDHWRRAs property specifies the Holt-Winters RRAs as described in the rrdcreate manual page.
Note, this setting will only affect newly created RRDs (targets).
Example:
RRDHWRRAs[myrouter]: RRA:HWPREDICT:1440:0.1:0.0035:288
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
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
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:
By defining ThreshDir to point to a writable directory, MRTG will only alert you when a threshold boundary has been crossed.
Example:
ThreshDir: /var/mrtg/thresh
If a threshold is broken, and you have a threshdir defined, then mrtg will send mail once the threshold becomes 'unborken' to avoid situations where broken and unbroken messages get sent in close succession, we only send an unbroken message once the current value is 0.1 (10%) away from the threshold. using the ThreshHyst config variable you can customize this value.
Example for 5%:
ThreshHyst: 0.05
Address of an SMTP server which is going to accept mail about Thresholds being broken and unbroken.
What is the sender address of the threshold mail.
Example:
ThreshMailSender: mrtg@example.com
Email address for Threshold related Mails. This will only work if a mailserver has been configured.
Example:
ThreshMailAddress[_]: admin@example.com ThreshMailAddress[router]:
This would bring threshold released mail to all but the target called 'router'.
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 and a mail will be sent to the ThreshMailAddress if specified. If the value ends in '%' then the threshold is defined relative to MaxBytes.
Works the same as TheshMinI but it acts when the value is higher than ThreshMaxI.
Its value will be assigned to the environment variable THRESH_DESC before any of the programs mentioned below are called. The programs can use the value of this variable to produce more user-friendly output.
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.
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 $router variable the unbroken threshold value, and the current parameter value.
These work the same as their *I counterparts, except on the Output (second) parameter.
When calling threshold scripts from within your cfg file you might want to pass some data on to the script. This can be done with the SetEnv configuration option which takes a series of environment variable assignments. Note that the quotes are mandatory. This does not work for external scripts. It is not possible to set environment variables per target.
Example:
SetEnv[myrouter]: EMAIL="contact_email@someplace.net"
HOST="www.some_server.net"
When using rrd based logging with HW RRAs defined. You can use the confidence bounds violations stored in the FAILURES RRA for threshold based alerts.
There the all target specific threshold variables have a Hold-Winters counterpart:
ThreshMailAddress -> HWThreshMailAddress ThreshMinI -> HWThreshMinI ...
The global variables for threshold checking are shared except for the
ThreshHyst -> HWThreshHyst
And HWThreshDesc sets the HWTHRESH_DESC variable.
To save yourself some typing you can define a target called '^'. The text of every Keyword you define for this target will be PREPENDED to the corresponding Keyword of all the targets defined below this line. The same goes for a Target called '$' 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[$]: Contact Peter Norton if you have any questions<HR>
To remove the prepend/append value, specify an empty value, e.g.:
PageTop[^]: PageTop[$]:
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 suppress 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
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 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.
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, complaining 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-message-dll.zip which does contain such a thing.
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 evaluating them
prof - add hires timing info the rrd calls
Example:
--debug="cfg,snpo"
An exit code of 0 indicates that all targets were successful. Generally speaking, most codes greater than 0 indicate that there was an unrecoverable problem. One exception to this is code 91, which indicates that at least one of the targets was successful. A partial listing of the codes follows:
0: All targets successful 2: Config error (can't read, fatal error in config, etc) 17: Another MRTG process is processing config 91: At least one target successful 92: No targets were successful
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>
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
Tobias Oetiker <tobi@oetiker.ch> and many contributors
| 2022-01-19 | 2.17.10 |