Perhaps I am trying to do the impossible. centos6, spamassassin, procmail, dovecot, postfix.
Postfix, by default, accepts all incoming mail to any user listed in the shadow/passwd and alias files.
I cannot find a way to stop that without manually blocking each non wanted user (like nobody, apache) without killing local delivery.
For most of the users listed in those files, who cares. However for one, root, this is a massive issue.
Root gets a lot of mail from errors on the system. Preventing local delivery (or through the alias file, delivery through root to another user) makes root never receive those important mails.
Not preventing root from incoming mails means root@example.com can be slammed with spam.
Local and external mail all seem to go through all of the programs (postfix, procmail, spamassassin, dovecot).
Local delivery of mails is needed for root.
What I would like is to just tell postfix to only allow incoming mail for user1 and user2 and reject all...but only from external sources, not locally sent mail.
Postfix does seem to allow you to limit who can send mail out of the server though...
I have 2 books on postfix here and spent many days online but I do not see the solution short of /dev/null or reject of all mail, local or external, of root.
perplexed.