(I am not sure if this question fits in serverfault.com. If not, forgive me.)
I maintain my client's ecommerce website and the credit card processing company requires PCI compliance. For that, our site needs to be scanned. I had to whitelist the scanner IP by setting up the iptables on my Ubuntu 14.04 server. Still the scanner can't scan the site.
Here's the message from the scanning company's support:
Even though there is no scan blocking on the website there is still something preventing our scanner form getting through. It is your responsibility to figure out what is causing the scanner not to see your site.
I asked what kind of scanner it was and he answered:
The software we use is Rapid Scan.
I don't know what to do. Please help me.