How to send e-mail from non-existing (autogenerated unique id) email?

Question

I'm the owner of a domain, and I'm currently hosting its mail (MX) in Google Apps for Business.

I have a catch-all account, so if someone replies an e-mail to [email protected], I have a robot that will read that e-mail and do some processing.

Problem is: How can I send an e-mail from that sender's address? I mean: I cannot create a userid for every generated id, and if I authenticate into Google SMTP with some user, the sender is automatically filled as that user address. (I'm aware that I can use any "verified aliases" as sender (or reply to), but I also cannot create an alias for every generated id.)

In summary: I need to send emails from non-existing e-mail address. How can I do that using 3rd party existing services (I don't want to host my own SMTP server, unless there is no easier solution).

Are there any hosted mail servers that will allow me to do that?

PS: As you may guess, it's a ticket-like system that should generate an unique e-mail address for each thread. (Yes, I know that I could use Subject for the unique identifier. Is that the best solution?)

Answer 1

Gmail lets you use the local part subaddress of the email address as an ad-hoc alias, e.g.

[email protected]

will be routed to [email protected], and you can use the local part/alias for filtering.

Though I haven't tried it, I suspect you can also send from [email protected] and it will be as if the email was sent from [email protected], and the From and/or Reply-To header of the email should contain the full [email protected].