Thanks for the link, but doesn't look quite like what I'm looking for. Sorry, I was not clear.
I signed up on some sites and entered a "fake" or "throwaway" email address, (ie.
twitter.com@mydomain.com, etc.), but these addresses do not exist in Zimbra and will not be created. The catchall catches and deliver the email to me. From there, I can tell from the "To:" field where the mail came from.
But with the catchall, spam of course is getting in. But I noticed a lot of the spam is using the same email addresses (addresses I never created, like
pren@mydomain.com,
lxh@mydomain.com,
info@mydomain.com,
sales@mydomain.com, etc.).
Is there a way to *list* specific email addresses to reject (at the smtp level so spamassassin isn't involved) and still be able to keep the catchall account? I know this won't solve the spam problem, but it should reduce a significant amount of spam.