The problem: You have a user with multiple aliases, such as a email@example.com username and a general firstname.lastname@example.org alias. You want to set an autoresponder for the main mailbox, but you don’t want to send an autoresponder message to messages directed to the sales alias.
MDaemon actually can do this although it’s not immediately obvious how.
The autoresponder list has a “whitelist”, to find it, open MDaemon –> Accounts –> Account Settings –> Autoresponders –> White List. This list is primarily a list of senders and recipients who should not receive an autoresponder.
Unfortunately this list compares addresses after alias processing has finished, so you can’t just enter an alias to the list. However, you can also match user-defined headers here, and if the header containing the string mentioned is found in the current message, the message won’t receive an autoresponder.
So in this example, you could place “X-MDRcpt-To: email@example.com” in the whitelist. Note that this header exists for all messages, not just messages where aliases are used, it simply contains the address the sender used.
For those that are curious, the \MDaemon\App\autorespexcept.dat file contains the list, for your manual editing pleasure.