These are the components that a successful Liferay installation will need:

1. Database. Options are  Oracle, MySQL, or Apache Derby
2. Email system. Options are
   • Washington IMAP+Sendmail
   • Cyrus IMAP+Postfix
   • Dovecot+Postfix
   • Microsoft Exchange 
3. LDAP
4. CAS Server for central authentication
5. Workflow engine
6. Lucene search engine