A redirect delivers the mail to both. The redirect on a box is an addition.
Mailgroup is a feature to redirect copies to several recicpients like this:
hotline@domain.com has the following members:
"admins@domain.com",
"developers@domain.com",
"emerge-domain@mac.com".
So any incoming mail on
hotline@domain.com will also be sent to these 3 accounts, also the remote box from mac.com. hotline then normally has no box.
So we should explain those possibilities:
Alias: receives mails on one certain box, with several names. e.g. "info@domain.com" has alias "sales". The box receives mails sent to
info@domain.com and
sales@domain.com
Redirect with box: deliver to the mailbox and deliver to the redirect-address, dont matter if the target is remote or not
Redirect with no box: Just deliver to another address, doesn't matter if it is local or remote
Mailgroup: delivers to all mentioned adresses, doesn't matter they are local or remote
Groups: delivers to several Mailgroups
Autoresponder: automatically answers an incoming mail with a prepared mail and delivers to the box