We have introduced a simple filtering system on email@example.com style addresses.
This was because these addresses are not passed through the standard mail filtering system, and it was possible for spam and/or viruses to be sent to these addresses and be received unfiltered.
There is now a new option in the control panel section ‘pop3/imap mailboxes’ to control the filtering on these addresses.
The ‘block external’ option will refuse to accept mail for firstname.lastname@example.org from a remote host and as a result, mail can only be sent to that pop3 mailbox via a forwarding rule.
The ‘virus scan" option will cause mail for that mailbox to be virus scanned, provided at least one mail forwarding rule for the corresponding domain has the ‘virus scan’ option turned on.