Parallels

Resolution

First of all you should choose a stable server available from the Internet (DNS, SSH, Apache, etc) ("Probe host", "Probe port" on the plugin configuration screen) which returns predefined string while connecting to it.
For example:
I choose SSH:
SSH on chosen "Probe host" returns "SSH-1.99-OpenSSH_3.6.1p2".

So to configure my test HSPc installation I use:
In your case any STABLE internet services which return predefined value can be used but not only SSH server.

 

Scenario:
1. Customer comes from src_ip.
2. After that proxycheck system scans some well known ports of src_ip to find out where proxy could run.
3. If proxies are found on src_ip, proxycheck tries to connect to our "Probe host" through the proxies found.
4. If a reply retrieved is exactly the same as we specified in "Reply" it means the src_ip the customer comes from is an open proxy.
5. Corresponding customer's order will not be processed before being approved by a provider.