OpenLDAP - OpenLDAP Software is an open source implementation of the Lightweight Directory Access Protocol.
389 Directory Server - Enterprise-class open source Linux LDAP server.
FreeIPA - FreeIPA is an integrated security information management solution combining Linux (Fedora), 389...
Microsoft Active Directory - Active Directory is a special-purpose database \ 8212; it is not a registry replacement.
Samba - Samba serves as an open source alternative to the traditional domain controller offered by Microsoft.
Keycloak - Open Source Identity and Access Management for modern Applications and Services.