MRTG is written in Perl and can run on Windows, Linux, Unix, Mac OS and NetWare.

MRTG uses the Simple Network Management Protocol (SNMP) to send requests with two object identifiers (OIDs) to a 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.

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.