public LdapName getSubjectBaseDN() throws GuacamoleException {
        return environment.getProperty(SSL_AUTH_SUBJECT_BASE_DN);
    }
Returns the base DN that contains all valid subject DNs. If there is no
such base DN (and all subject DNs are valid), null is returned.

@return
    The base DN that contains all valid subject DNs, or null if all
    subject DNs are valid.

@throws GuacamoleException
    If the configured base DN cannot be read or is not a valid LDAP DN.
extensions/guacamole-auth-sso/modules/guacamole-auth-sso-ssl/src/main/java/org/apache/guacamole/auth/ssl/conf/ConfigurationService.java