MRTG-REFERENCE(1) mrtg MRTG-REFERENCE(1)
NAME
mrtg-reference - MRTG 2.14.7 configuration reference
OVERVIEW
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.
SYNTAX
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
Example:
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.
GLOBAL KEYWORDS
WorkDir
WorkDir specifies where the logfiles and the webpages should be cre
ated.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
OPTIONAL GLOBAL KEYWORDS
HtmlDir
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.
Example:
Htmldir: /www/mrtg/
ImageDir
ImageDir specifies the directory where the images live. They should be
under the html directory.
Example:
Imagedir: /www/mrtg/images
LogDir
LogDir specifies the directory where the logs are stored. This need
not be under htmldir directive.
Example:
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.
Example:
Forks: 4
EnableIPv6
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
EnableSnmpV3
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
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
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:
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.
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.
MaxAge
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).
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
NoMib2
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.
Example:
NoMib2: Yes
SingleRequest
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.
Examples
SingleRequest: Yes
SnmpOptions
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
ported:
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.
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.
IconDir
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/
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
Language
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
tions).
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
Example:
Language: danish
LogFormat
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
LibAdd
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/
PathAdd
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/
RunAsDaemon
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
gram:
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 min
utes
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.
ConversionCode
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
follows:
Target[myrouter]: 1.3.6.1.4.1.999.1&1.3.6.1.4.1.999.1:public@mydeviceLength2Int
See "Extended Host Name Syntax" below for complete target definition
syntax information.
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.
Target
With the Target keyword you tell mrtg what it should monitor. The Tar
get keyword takes arguments in a wide range of formats:
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[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
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, since we now use 64 bit instead of the normal 32
bit.
Example:
Target[myrouter]: 2:public@router1:::::2
SNMPv3
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.
Example:
Target[myrouter]: 2:router1:::::3
SnmpOptions[myrouter]: username=>user1
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 traf
fic rates.
Example:
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.
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
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:
Example:
Target[myrouter]: ifInErrors.1&ifOutErrors.1:public@myrouter
SnmpWalk
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 (!).
Example:
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
--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]: 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[myrouter]: ifInErrors/1.2.3.4&ifOutErrors/1.2.3.4:public@myrouter
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
--ifref=descr.
Example:
Target[myrouter]: \My-Interface2:public@wellfleet-fddi.domain
Target[ezci]: -\My-Interface2:public@ezci-ether.domain
Target[myrouter]: 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[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
switches.
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]: 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[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.
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&!0a-00-10-23-44-51:public@myrouter
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
--ifref=type.
Example:
Target[myrouter]: %13:public@wellfleet-fddi.domain
Target[ezci]: -%13:public@ezci-ether.domain
Target[myrouter]: 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[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
lows:
community@router[:[port][:[timeout][:[retries][:[backoff][:[version]][name]]]]]
where the meaning of each parameter is as follows:
port
the UDP port under which to contact the SNMP agent (default:
161)
timeout
initial timeout for SNMP queries, in seconds (default: 2.0)
retries
number of times a timed-out request will be retried (default:
5)
backoff
factor by which the timeout is multiplied on every retry
(default: 1.0).
version
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.
Example:
3:public@router1:::::2
name
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.
Example:
1.3.6.1.4.1.999.1&1.3.6.1.4.1.999.2:public@mydevice:161::::2Length2Int
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 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.
Example:
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.
Example:
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
count
Line 2
current state of the second variable, normally outgoing bytes
count
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.
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 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.
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 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.
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: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
1:public@CiscoA.
MaxBytes
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 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.
Example:
MaxBytes[myrouter]: 1250000
Title
Title for the HTML page which gets generated for the graph.
Example:
Title[myrouter]: Traffic Analysis for Our Nice Company
OPTIONAL PER TARGET KEYWORDS
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[myrouter]: 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@194.64.66.250 + 2:public@194.64.66.250
RouterUptime[kacisco.comp.edu]: public@194.64.66.250
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 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
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 |
