When we send email from an alias, the headers include the login/authenticated ID of the sender. So when I login as foo@domain and send as bar@domain, the recipient still sees foo in the header. I don't think it's appropriate to reveal the login name to recipients. And while we can easily disable some alias addresses, if a spammer gets the primary mailbox ID, we're stuck processing more spam on that account over time. So when creating mailboxes, I'd like to use internal names, and only expose external names in headers. In the Mailbox screen we have a checkbox for "Enable receiving", but I believe this is a master switch to disable that mailbox and all associated aliases. I would just want to disable receiving on the mailbox name, but continue receiving on all aliases. I believe one way to do this would be to create sieve filters to reject all mail sent directly to a mailbox ID. To avoid having to update that manually it would be necessary to create a lookup table which gets upated from ISPConfig. This gets complicated, so I'd prefer a better way. Suggestions? Thanks!