You can easily test out Linux/UNIX network Load using standard dd and scp commands.
=> Use dd to create a large file.
=> Use scp to copy file from one system to another system. scp copies files between hosts on a network. It uses ssh for data transfer, and uses the same authentication and provides the same security as ssh. Make sure both local and remote system owned by you i.e. co-operation from another host on the network is required for test network load.
Step # 1: Create a large file
Use dd command as follows to create a large file (e.g. 1024M x 2count = 2GB):
$ dd if=/dev/zero of=/tmp/big.file bs=1024M count=50
Step # 2: Use scp to transfer file
Now copy a file to remote host using scp:
$ scp /tmp/big.file email@example.com:/tmp
Any error or crash indicates problem with system load testing.
Please note that if the server has two+ network cards, make sure that the test is run and uses each of the network cards. Disable NIC using ifconfig command or alter routing using route command for testing purpose.