Adding To: header to incoming mails using hMail server

Question

I have just enabled plus-addressing with my instance of hMailServer. Now, whenever I sign up for an online service, I can easily provide a unique email address for that service. This is part spam-prevention and part curiosity. If the unique email address I provide starts being spammed, I can simply turn it off and know exactly where my address was leaked from.

Now, the problem arises in that some incoming spam emails do not specify a To: header, making it impossible (without reading the SMTP logs) to find out which email address is the intended recipient.

I know that hMail supports scripted extensions for mail processing (See OnAcceptMessage for example).

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So then, with hMailServer; In the case where the incoming mail is from an unauthenticated sender, is it possible to add the parameter of the SMTP command RCPT TO: as a header to the incoming email?

Answer 1

You're erroneously using the message headers when you should be using the message envelope. The To: header is entirely irrelevant for figuring out the message recipient — as should have been obvious from the fact that those messages entirely without To: headers were successfully routed to you. The hMailServer documentation even discusses this.

It moreover tells you about the list of recipients for a message before it is delivered. It furthermore tells you where the setting is for the conventional Delivered-To: header that conventionally records envelope recipients after messages have been delivered and their envelopes discarded.