Editing Multi Router Traffic Grapher

{{ref improve|date=July 2014}}
{{Short description|Software for tracking traffic load network links}}
{{redirect|MRTG|text=It may also be an abbreviation for [[mortgage loan]]}}
{{Infobox software
| name = MRTG
| logo = [[Image:Mrtg logo2.png|205px|MRTG logo]]
| caption = Multi Router Traffic Grapher
| developer = Tobi Oetiker
| latest_release_version = 2.17.10
| latest_release_date = {{start date and age|2022|1|19}}<ref>{{cite web|url=https://oss.oetiker.ch/mrtg/pub/?M=D |title=Index of /mrtg/pub|date= |accessdate=2023-02-09}}</ref>
| operating_system = [[Cross-platform]]
| programming_language = [[Perl]]
| genre = Bandwidth monitor
| license = [[GNU General Public License]]
| website = {{url|https://oss.oetiker.ch/mrtg/}}
}}

The '''Multi Router Traffic Grapher''' ('''MRTG''') is [[free software]] for [[Network monitoring|monitoring]] and [[Network traffic measurement|measuring]] the traffic load on [[computer network|network]] links. It allows the user to see traffic load on a network over time in graphical form.

It was originally developed by Tobias Oetiker and Dave Rand to monitor [[router (computing)|router]] traffic, but has developed into a tool that can create graphs and statistics for almost anything.

MRTG is written in [[Perl]] and can run on [[Microsoft Windows|Windows]], [[Linux]], [[Unix]], [[Mac OS]] and [[Novell NetWare|NetWare]].

[[Image:MRTG Graph from My Router localhost eth0-day.png|frame|A sample MRTG bandwidth graph.]]

==How it works==
===SNMP===
MRTG uses the [[Simple Network Management Protocol]] (SNMP) to send requests with two [[object identifier]]s (OIDs) to a device. The device, which must be SNMP-enabled, will have a [[management information base]] (MIB) to look up the OIDs specified. After collecting the information it will send back the raw data encapsulated in an SNMP protocol. MRTG records this data in a log on the client along with previously recorded data for the device. The software then creates an [[HTML]] document from the logs, containing a list of graphs detailing traffic for the selected devices in the server.

===Script output===
Alternatively, MRTG can be configured to run a script or command, and parse its output for counter values. The MRTG website contains a large library of external scripts to enable monitoring of SQL database statistics, firewall rules, CPU fan RPMs, or virtually any integer-value data.

==Features==
{{Prose|section|date=August 2017}}
* Measures two values (I for Input, O for Output) per target.
* Gets its data via an [[Simple Network Management Protocol|SNMP]] agent, or through the output of a command line.
* Typically collects data every five minutes (it can be configured to collect data less frequently).
* Creates an [[HTML]] page per target that features four graphs ([[Graphics Interchange Format|GIF]] or [[Portable Network Graphics|PNG]] images).
* Results are plotted vs time into day, week, month and year graphs, with the '''I''' plotted as a full green area, and the '''O''' as a blue line.
* Automatically scales the Y axis of the graphs to show the most detail.
* Adds calculated Max, Average and Current values for both '''I''' and '''O''' to the target's HTML page.
* Can also send warning emails if targets have values above a certain threshold.

== See also ==
{{Portal|Free and open-source software}}
* [[RRDtool]] - Reimplementation of MRTG's graphing and logging features
* [[Munin (network monitoring application)|Munin]] - Another monitoring application with web interface, based on RRDtool
* [[Cacti (software)|Cacti]] - A similar tool using [[RRDtool]]

== References ==
{{Reflist}}

==External links==
* {{Official website|oss.oetiker.ch}}

[[Category:Internet Protocol based network software]]
[[Category:Network analyzers]]
[[Category:Free network management software]]