You can create Allow and Deny filters for the IMAP, POP, or HTTP services. You can also create them for SMTP services, but they have little value because they only apply to authenticated SMTP sessions. See Chapter 18, Mail Filtering and Access Control
Command Line. You can also specify access and deny filters at the command line as follows:
To create or edit access filters for services:
where service is pop, imap, or http and filter follows the syntax rules described in 23.7.2 Filter Syntax.
To create or edit deny filters for services:
configutil -o service.service.domainnotallowed -v filter