Gmail allows users to filter e-mails based on many things such as words, sender, etc. and once matched it can auto-reply each filtered email with a canned response (requires Canned Responses lab], among other actions. Those replies seem to be necessarily sent from the Gmail address of the account doing the filtering and they include a +canned.response or +auto.reply "tag" in the email address.
Is there any "easy" way (even if another 3rd party service or a Unix server is needed) to send those auto-canned-responses from some external SMTP server as it is possible to do when sending manual replies from Gmail web app?
By doing so we could use -for example- a more corporate-style email address such as
firstname.lastname@example.org instead of