RazDC is described as 'It's an active directory replacement built on CentOS + Samaba4. Includes support for Directory, DNS, DCHP, and NTP type services'. There are more than 10 alternatives to RazDC for a variety of platforms, including Linux, Mac, Windows, BSD and Self-Hosted solutions. The best alternative is Zentyal. It's not free, so if you're looking for a free alternative, you could try Samba or Univention Corporate Server. Other great apps like RazDC are FreeIPA (Free, Open Source), Microsoft Active Directory (Paid), SambaBox (Paid) and OpenLDAP (Free, Open Source).
Zentyal is a native Microsoft Active Directory implementation on Linux incorporating all the network services required in a small and medium business environment: Directory & Domain Server, Mail Server, Gateway and Infrastructure Server.
Samba is the standard Windows interoperability suite of programs for Linux and Unix. Since 1992, Samba has provided secure, stable and fast file and print services for all clients using the SMB/CIFS protocol, such as all versions of DOS and Windows, OS/2, Linux and many others.
FreeIPA is an integrated security information management solution combining Linux (Fedora), 389 Directory Server, MIT Kerberos, NTP, DNS, Dogtag (Certificate System). It consists of a web interface and command-line administration tools.
SambaBox is an integrated enterprise domain appliance which works flawlessly with Windows AD environment. SambaBox offers, Integrated DNS, DHCP, CA and SaltStack with web based management on hight secure environment.
OpenLDAP Software is an open source implementation of the Lightweight Directory Access Protocol. The suite includes: slapd - stand-alone LDAP daemon (server) libraries implementing the LDAP protocol, and utilities, tools, and sample clients.
Enterprise-class open source Linux LDAP server. Hardened by real-world use, full-featured, supports multi-master replication. 389 DS can be downloaded for free and set up in less than an hour using the graphical console.
Go-lang LDAP Authentication (GLAuth) is a secure, easy-to-use, LDAP server w/ configurable backends. - Centrally manage accounts across your infrastructure - Centrally manage SSH keys, Linux accounts, and passwords for cloud servers.
OpenDJ is a directory server which implements a wide range of Lightweight Directory Access Protocol and related standards, including full compliance with LDAPv3 but also support for Directory Service Markup Language (DSMLv2).