> One important thing to keep in mind when load-testing is that there are only so many socket connections you can have in Linux. This is a hard-coded kernel limitation, known as the Ephemeral Ports Issue. You can extend it (to some extent) in /etc/sysctl.conf; but basically, a Linux machine can only have about 64,000 sockets open at once. So when load testing, we have to make the most of those sockets by making as many requests as possible over a single connection. In addition to that, we'll need more than one machine to do the load generation. Otherwise, the load generators will run out of available sockets and fail to generate enough load.

If the # of ports is the bottle neck, you can configure more IPs on a single host.