How to restrict receiving emails from external addresses to Zimbra part of the address and mailing?

Good afternoon, colleagues!
There is a mail server CentOS 5 + Zimbra 7.2.7
There was a need to close the option of receiving e-mails from external addresses to mailboxes and parts lists. Tell me, please, what means it is possible to do.
July 8th 19 at 11:13

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