What is Liferay Portal?

Liferay Portal is a Java web application. In a web application, a user types in a Uniform Resource Locator (URL) string in a browser address box and fires it. The browser sends the URL as a request to a corresponding application server and waits. The application server receives the request and processes data according to parameter values in the received URL. It sends a Hypertext Markup Language (HTML) format file to the requesting browser as a response. The browser interprets the HTML file and renders a webpage to the user. All the typical characteristics of a web application apply to the Liferay Portal.

The following is a deployment diagram for a Liferay Portal instance:

In this deployment diagram, a user accesses a Liferay Portal site with a web browser. Liferay receives the request and sends a request to the Single Sign On (SSO) server for authentication. The SSO server goes to the Lightweight Directory Access Protocol (LDAP) server to check the user's credentials. When that is successful, the SSO server tells Liferay Portal that the user is authenticated. Liferay Portal responds to the user request with a home landing page.

The Liferay Portal also runs portlet artifacts (please read on for an explanation of portlets). It relies on a database server to store data. It uses the mail server to send mails to the portal users. Optionally, Liferay Portal may also use other servers for additional functionalities.