Apache is a free and open-source cross-platform web server software.
CentOS is a Linux distribution that provides a free, community-supported computing platform functionally compatible with its upstream source, Red Hat Enterprise Linux (RHEL).
Google Analytics is a free web analytics service that tracks and reports website traffic.
Mod_dav is an Apache module to provide WebDAV capabilities for your Apache web server. It is an open-source module, provided under an Apache-style license.
mod_ssl is an optional module for the Apache HTTP Server. It provides strong cryptography for the Apache web server via the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) cryptographic protocols by the help of the open-source SSL/TLS toolkit OpenSSL.
OpenSSL is a software library for applications that secure communications over computer networks against eavesdropping or need to identify the party at the other end.
PHP is a general-purpose scripting language used for web development.