Checkpcidss.com does what the name suggest. It is an online application for scanning your website/server against PCI DSS security compliance. It is developed in Python using network socket programming. Checkpcidss.com won't scan all ports in your server.This will support almost all web hosting servers. It have some predefined services and ports, which will scan and show the critical results. So you can scan your website/server without much firewall issue.