Zimbra_8.7.5 - reject_unlisted_sender

[splicelid]

Hi Guys, I have Zimbra 8.7.5 in production and I read a wiki for rejecting unlisted senders. I execute this command:

zmprov mcf zimbraMtaSmtpdRejectUnlistedSender yes
zmmtactl restart
zmconfigdctl restart

But in my /opt/zimbra/conf/zmconfigd/smtpd_sender_restrictions.cf I don't see this line :
reject_unlisted_sender

My question is should this line(reject_unlisted_sende) be there or not ? is this a bug ?

thank you in advance!