Fess is very powerful and easily deployable Enterprise Search Server. You can install and run Fess quickly on any platforms, which have Java runtime environment. Fess is provided under Apache license.
Very Easy Installation/Configuration
Apache License (OSS)
OS-independent (Java Application)
Crawler for Web/File System/DB/Windows Shared Folder(SMB)
Support many document types, such as MS Office, PDF, Zip archive,…
Support a web page for BASIC/DIGEST/NTLM/FORM authentication
Contain elasticsearch as a search engine (unlimited scalability)
Provide UI as a responsive web design (support any device)
Provide a browser based administrative page (admin console)
Support secure search (access control with LDAP/Active Directory)
Single Sign On support with SAML/OpenIDConnect
Support JSON/GSA format of search results
Provide search/click log and statistics
Learning To Rank support
Fess is distributed under Apache license 2.0 and available for free.
Fess is Open Source Software.
Project Site: fess.codelibs.org