Synology Directory Server Technical Specifications

Centrally secures and manages identities of users, groups, and devices within an organization
Automates and integrates identity and access control into IT operations
Domain functional level: equal to Windows Server 2008 R2
Samba version: 4.10
Supports a single domain only
Supports custom NetBIOS domain names
After a domain is created, SMB signing will be enabled automatically, which may reduce read/write performance during SMB file transfer

Maximum objects support: 100,000
- The actual figure depends on the capability of your Synology NAS
Maximum groups that a user can join: 50
Supports roaming user profiles and home folder creation (Learn more)
Limitations: User and group names do not support special characters: {}|^[]?=:+/*()$!"#%&',;<>@\~`

Supports setting up one primary domain controller and secondary domain controllers
- The primary domain controller must be a read-write domain controller (RWDC)
- A secondary domain controller can be either a RWDC or a read-only domain controller (RODC)
  - Supports up to one RWDC
  - Supports up to ten RODCs
The secondary domain controller only works with domains created by Synology Directory Server
Windows Servers that are deployed as RWDCs synchronize data to RODCs every five minutes
The list of user accounts authenticated on a RODC can only be displayed when the RODC is joined to a Windows AD

Supports domain clients on
- Microsoft Windows 7 and above
- macOS
- Linux (via Samba Winbind module)
Limitations: Binding of LDAP client accounts is not supported

Adopts Kerberos-based authentication
Supports TLS domain controller certification
Supports account single sign-on and Windows NTLM
Supports Active Directory group-based access controls
Increases account security via account lockout policies and password strength policies (e.g., expiration period, password length, and historical record comparison)

Sets group membership and policies via RSAT (Learn more)
Integrated with DNS Server to register DNS settings upon domain creation
Supports audit logging in Log Center
Supports Synology High Availability for failover and continuous service availability
Limitations
- The Active Directory module for Windows PowerShell is not supported
- Distributed File System Replication (DFSR) is not supported

Supports scheduled backup and restoration of directory server configurations via Hyper Backup
Limitations
- Backups of Synology Directory Server 4.10.15-0244 and above versions cannot be restored on DSM 6.2
- Backups of Active Directory Server 4.4.5-0077 or earlier versions cannot be restored once the package is updated to Synology Directory Server 4.4.5-0086 or above. We recommend creating a new backup task for the updated package in Hyper Backup and running the task immediately