This feature is specific to On-premises solution where you can add the authentication types like Active Directory, LDAP, RADIUS and, Digital Certificate.
To add authentication servers
Authentication Type - There are four options to choose - Active Directory, LDAP, RADIUS and, Digital Certificate. This indicates the type of the Remote Authentication Server if it is an LDAP server, a Windows Active Directory, a RADIUS Server or a Digital Certificate. The configuration values for Active Directory and LDAP are same.
IP/FQDN - The hostname or the IP address of the Remote authentication server. Example: [mydc.example.com], [X.X.X.X] (ip address), [company.com].
PRIMARY RADIUS SERVER
BACKUP RADIUS SERVER
IP/FQDN
Port - The default LDAP over TLS port number is TCP 636. The default LDAP(unencrypted) port number is TCP 389, but you can select from the Standard port choices drop-down menu for more options. If you are using a custom listening port on your LDAP server, specify it here.
Name - Enter the name to identify the authentication server.
CA Certificate - From the drop down list, choose any existing certificates. To add a new certificate, click Edit icon and select Add CA Certificate.
Select Import a local end-user certificate with private key from a PKCS#12 (.p12 or .pfx) encoded file.
Next, enter the Certificate Name and the Certificate Management Password (the password you defined when creating the .pfx file). Click Import.
Import a CA certificate from a PKCS#7 (.p7b), PEM (.pem) or DER (.der or .cer) encoded file
Click Add File and browse to locate and open your Certificate .pfx file. Click Import to import the selected certificate.
User Directory LDAP Schema
USER OBJECTS
USER DIRECTORY LDAP SCHEMA
Allow Only AD Group Members - Toggle the button to allow or deny AD Group Members. When enabled, it allows only those users that are members of the specified Active Directory Groups to login into NSM. With this option, it is also necessary to select the Host Type as [Active Directory] on the Settings Panel.
Active Directory Group(s) - Specify the AD Group names, members of which should be allowed to login into NSM. Multiple AD Groups can be specified as semicolon delimited. Example: [NSMUsers], [ADGroup1;AD group2;NSM Users;Group4]