nginx (pronounced engine-x) is a Web server and a reverse proxy server for HTTP, SMTP, POP3 and IMAP protocols, with a strong focus on high concurrency, performance and low memory usage. wikipedia.org

Internet Information Services (IIS) _ formerly called Internet Information Server _ is a web server application and set of feature extension modules created by Microsoft for use with Microsoft Windows. wikipedia.org

Ubuntu is a computer operating system based on the Debian Linux distribution and distributed as free and open source software. It is named after the Southern African philosophy of Ubuntu ("humanity towards others").

The Parallels Plesk Panel software package is a commercial web hosting automation program. It allows a server administrator to set up new websites, reseller accounts, e-mail accounts, and DNS entries through a web-based interface. wikipedia.org

Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide communication security over the Internet. TLS and SSL encrypt the segments of network connections above the Transport Layer, using asymmetric cryptography for key exchange, wikipedia.org

The Payment Card Industry Data Security Standard (PCI DSS) is an information security standard for organizations that handle cardholder information for the major debit, credit, prepaid, e-purse, ATM, and POS cards. wikipedia.org