How to load test an IP rotation proxy

Load testing

I usually use ab for load testing servers. Recently I wanted to load test an IP rotation proxy. IP rotation proxies are regular proxies that run every single request through a different IP.

It’s very easy to load test a proxy with ab . Here is an example.

ab -c 100 -n 1000 -P <proxy-username>:<proxy-password> -X <proxy-hostname>:<proxy-port>

The downside of this method are:

  • ab makes no distinction between failures dues to the proxy, and those dues to the target endpoint,
  • ab can’t collect the HTTP responses, so it’s impossible to check how the rotation is performing (how often IPs are repeating.)

It’s super simple however to do this with a for loop

for i in {1..1000}; do
    curl -U <proxy-username>:<proxy-password> -x <proxy-hostname>:<proxy-port> >> output.txt &

Then to check if there are any IP duplicates, simply run uniq to produce a csv you can import in Excel and visualize as a chart:

sort output.txt | uniq -c > ouput.csv