Nagios Support Forum

The functionality you're looking for doesn't currently exist as that data is not stored in XI in a queryable form. You would need to write your own API endpoint to parse the /etc/mrtg/conf.d/X.X.X.X.cfg data if you need it accessible via the API, this is not something that exists today. You could also write a plugin that parses that file and displays that information in the service output (which would be available in the service output) but a plugin doesn't exist for that today, you would need to write it. You could also setup services that check the max speed of the port as well (there is likely a plugin for this) but that service would be doing the checking and it wouldn't rely on the /etc/mrtg config, it would grab it from the device.

See here on your system for the custom API endpoint info: