- Ben Morrow ben@morrow.me.uk 2013.02.16 04:49:
The setup given in that howto will accept mail for any user at one of the domains listed in virtual_mailbox_domains, and mail for nonexistent users will then be bounced by Dovecot. This is a very bad idea, since you'll end up becoming a backscatter source; you should set up a separate Postfix table listing the valid users at those domains, and put that table in virtual_mailbox_maps. (You don't want to use /etc/postfix/virtual for this, you want a separate table.)
It will verify the recipients before accepting the mail:
reject_unverified_recipient http://www.postfix.org/postconf.5.html#reject_unverified_recipient
I don't think the overhead of duplicating user checks on both ends is justified until this process is automated. Above will instruct the SMTP Server to verify the recipient address before accepting mail. This is what you want and it works dynamic out of the box. A better reason to use separate aliasing on the Postfix side is to rewrite addresses for the Dovecot Mailboxes. If you'd want to have a mailbox with several addresses in Dovecot you'd need to create dummy users for this while you can just alias them in Postfix.
Regards Thomas