Reasons To Choose Packet Sniffing

It is important to understand that the packet sniffer can only access and inspect data packets that actually flow through the network interface(s) of the machine running the PRTG software.

This is fine if you only want to monitor the traffic of this machine (e.g. your web server). But in switched networks only the traffic for a specific machine is send to each machine’s network card, so PRTG can usually not see all the traffic of the other machines in the network.

If you also want to monitor the traffic of other devices in your network you must use a switch that offers a “monitoring port” or “port mirroring” configuration (Cisco calls it “SPAN”).

In this case the switch sends a copy of all data packets traveling through the switch to the monitoring port. As soon as you connect the machine that runs PRTG to the monitoring port the packet sniffer is able to analyze the complete traffic that passes through the switch.

Another option is to use the PC running PRTG Traffic Grapher as a gateway for all the other computers.