# Introduction to Plesk

Plesk consists of the following main components:

- The front-end GUI service. The GUI, served with the Internet Information Services (IIS) server, is the main means of interaction with Plesk.

- Plesk core. The core processes management requests from the Plesk GUI, command line interface, and XML API. The core contains scripts, binary files and other resources used to link Plesk components with each other and with external services.

- The Plesk’s main database called `psa`. The database stores information about Plesk objects, such as IP addresses, domains, user accounts, and many others. The database is served by MySQL/MariaDB or the Microsoft SQL database engine.

- Plesk’s configuration files.

- Plesk’s log files.

- Command-line utilities. Command-line interface allows integration of third-party software with Plesk, and provides the means to manage Plesk through the server console. For more information about the Plesk command-line interface, refer to Plesk Command Line Reference.

- XML API. This interface is another way to integrate third-party software with Plesk. It allows to manage Plesk objects from remote by sending specifically structured XML packets and receiving responses from Plesk. For more information on XML API, refer to Developer’s Guide: Read Me First and XML API Protocol Reference.

## Services Managed by Plesk

Plesk uses standard packages for the following services:

IIS as a set of Internet services including HTTP, FTP, and others.

FTP servers - ServU, Gene-6, used as alternative FTP servers.

Mail servers - MailEnable, IceWarp (Merak), CommuniGate Pro, or SmarterMail.

Microsoft DNS - used as the domain name server.

MySQL/MariaDB used to store the Plesk’s database called psa that is used for administrative purposes

Microsoft SQL or MySQL/MariaDB - used as a database server by Plesk users.

Tomcat - used as an infrastructure for servlet and JSP-based applications shipped in the *.war format.

JDK (j2sdk) - used as a library for java applications.

SpamAssassin - used as protection against spam email messages.

Plesk Premium Antivirus, Sophos Anti-Virus for Servers, or IceWarp Antivirus - used as email antivirus tools.

## Files and Directories Used by Plesk Installations

Plesk and its components are installed by default in the directory `C:\Program Files (x86)\Plesk\` on a physical server, or `C:\Program Files\Plesk\` in the Virtuozzo containers environment. The default installation directory is referred to as `%plesk_dir%` in the following list. Some of the subdirectories with corresponding components are listed below.

`%plesk_dir%admin\` - The core components used by the Plesk GUI.

`%plesk_dir%admin\plib\` - Plesk’s PHP files.

`%plesk_dir%admin\bin\` - Binary utilities.

`%plesk_dir%bin\` - Binary utilities.

`%plesk_dir%etc\` - Configuration files.

`%plesk_dir%MailServer\` - Mail servers.

`%plesk_dir%backup\` - Backup files.

`%plesk_dir%dns\` - BIND name server files.

`%plesk_dir%MySql\` - Plesk’s MySQL database server.

`%plesk_dir%Databases\` - Database servers for serving user data.