The check_mrtg Plugin

check_mrtg v2.3git (monitoring-plugins 2.3git)
Copyright (c) 1999 Ethan Galstad <>
Copyright (c) 1999-2007 Monitoring Plugins Development Team

This plugin will check either the average or maximum value of one of the
two variables recorded in an MRTG log file.

check_mrtg -F log_file -a <AVG | MAX> -v variable -w warning -c critical
[-l label] [-u units] [-e expire_minutes] [-t timeout] [-v]

 -h, --help
    Print detailed help screen
 -V, --version
    Print version information
    Read options from an ini file. See
    for usage and examples.
 -F, --logfile=FILE
   The MRTG log file containing the data you want to monitor
 -e, --expires=MINUTES
   Minutes before MRTG data is considered to be too old
 -a, --aggregation=AVG|MAX
   Should we check average or maximum values?
 -v, --variable=INTEGER
   Which variable set should we inspect? (1 or 2)
 -w, --warning=INTEGER
   Threshold value for data to result in WARNING status
 -c, --critical=INTEGER
   Threshold value for data to result in CRITICAL status
 -l, --label=STRING
   Type label for data (Examples: Conns, "Processor Load", In, Out)
 -u, --units=STRING
   Option units label for data (Example: Packets/Sec, Errors/Sec,
   "Bytes Per Second", "%% Utilization")

 If the value exceeds the <vwl> threshold, a WARNING status is returned. If
 the value exceeds the <vcl> threshold, a CRITICAL status is returned.  If
 the data in the log file is older than <expire_minutes> old, a WARNING
 status is returned and a warning message is printed.

 This plugin is useful for monitoring MRTG data that does not correspond to
 bandwidth usage.  (Use the check_mrtgtraf plugin for monitoring bandwidth).
 It can be used to monitor any kind of data that MRTG is monitoring - errors,
 packets/sec, etc.  I use MRTG in conjunction with the Novell NLM that allows
 me to track processor utilization, user connections, drive space, etc and
 this plugin works well for monitoring that kind of data as well.

 - This plugin only monitors one of the two variables stored in the MRTG log
   file.  If you want to monitor both values you will have to define two
   commands with different values for the <variable> argument.  Of course,
   you can always hack the code to make this plugin work for you...
 - MRTG stands for the Multi Router Traffic Grapher.  It can be downloaded from

Send email to if you have questions regarding
use of this software. To submit patches or suggest improvements, send email