Use an LDAP editor like LDAPadmin.
Connect to LDAP server running on Synology NAS.
Host: Synology Nas server
Port: 389
base: cn=config
Simple authentication
TLS selected or deselected
Username: cn=config
password= same as root user LDAP server
After logging in
select cn=config and edit entry
add attribute or change value attribute olcTLSCipherSuite with your values.
