Use (or to listen on a particular network port on the first system running Linux. Type the following command into a terminal and press Enter.
nc -l -k -p 12345
This tells the system to listen for network traffic on port 12345 and to keep listening.
Now that the first system is set up to listen on port 12345, on the second system type the command below, changing the IP address, e.g. x.x.x.x to that which is assigned to the first system.
dd if=/dev/zero bs=16000 count=6250 | nc -v x.x.x.x 12345
The first part of the command tells the machine to copy 100MB of data from /dev/zero in 16 kilobyte blocks. The part after the pipe tells it to send that to the first system over port 12345. The results displayed will indicate the speed of the network, measured in megabytes per second.
Once you're done testing, go to the terminal on Desktop and use CTRL-C to stop netcat on the first system.