Troubleshooting Tip: How to determine the speed from local host to its upstream FortiGate

[Renante_Era]

Description	This article demonstrates how to determine the speed of a local host to its upstream FortiGate using iPerf3.
Scope	FortiGate.
Solution	Determining the speed between the local host and the upstream FortiGate is necessary when the host is experiencing a slow connection between the local host to the internet, the local host to a host across the IPsec VPN tunnel, or the local host to another host across different network subnet. Download and extract the downloaded zip file. Open the Downloads folder using File Explorer in Windows if the zip file was saved in the Downloads folder. Next, 'right-click' the downloaded file, select Extract All, and select Extract. Open a Command Prompt and determine the IP address of the local host using ipconfig. Run iperf3 -s on the command line. The default port is 5201 and the port can be manually specified using iperf3 -s -p <port number>. For instance, iperf3 -s -p 443.                                                                                       Configure the iperf settings on the FortiGate CLI and initiate the client test. The command diag traffictest ? shows the available options.                                                                                                                    Identify the interface where the local host is connected and configure traffictest's server and client interface. For instance, if the local host is connected to a wireless SSID that is a member of FortiGate's software switch lan, then the commands are as follows: diag traffictest server-intf lan diag traffictest client-intf lan                                              Initiate the iPerf client test where FortiGate is the user. diag traffictest run -c <IP address> -p 5201 -i 10 -f m -b 0 -t 60 Repeat the iperf test in a reverse direction. diag traffictest run -c <IP address> -p 5201 -i 10 -f m -b 0 -t 60 -R                             -c -- iPerf is running in client mode, define IP address of iPerf server -p -- the port on which iPerf server is listening -i -- interval time in seconds (default: 0) -f -- format to print bandwidth values ['k' = Kbits/sec, 'K' = KBytes/sec, 'm' = Mbits/sec, 'M' = MBytes/sec] -b -- target bandwidth (default: 1 Mbit/sec for UDP, unlimited for TCP) -t -- time in seconds the iPerf test will run (default: 10 seconds) -R -- reverse mode used to measure download speed (server sends, client receives) More command line options can be found in iPerf documentation. https://iperf.fr/iperf-doc.php Note: Press Ctrl+C to stop iPerf3 on Windows Command Prompt. Ideally, connect the local host directly to FortiGate instead of a wireless connection to WiFi SSID.