Thank you for providing a PR for an issue you encountered. Usually, we require users to open an issue first to discuss the matter, because:

If new recipient exists as alias in db then setup is throwing error.

That behavior seems reasonable to me. Why would you change that? Can you describe in more detail what you mean here?

It would be very nice of you could open a new bug report issue and describe your problem in more detail there. Thank you :)

#3262

It's now an issue. It is a email forwarding feature. How to forward email if you blocked alias for email account?

How to forward email if you blocked alias for email account?

We did not block alias for all email accounts, we blocked aliases that are equal to accounts.

It's now an issue. It is a email forwarding feature.

Not quite; you're not actually forwarding / relaying an email, because this would imply that either DMS is the new sender (forwarding) or DMS is not the addressee but an intermediate MTA (relaying). You somehow want Gmail to act on DMS. @polarathene has proposed a solution in #3262 (comment) for the issue you raised.

Not quite; you're not actually forwarding / relaying an email, because this would imply that either DMS is the new sender (forwarding) or DMS is not the addressee but an intermediate MTA (relaying). You somehow want Gmail to act on DMS. @polarathene has proposed a solution in #3262 (comment) for the issue you raised.

It was not my concern that there's an alias for account. I raised other concern

How to forward email if you blocked alias for email account?

I think what you would like is relay_domains support. This allows a separate transport to relay mail received.

If it is not acceptable to store mail on DMS and retrieve it like suggested, this should let mail for [email protected] to arrive and be relayed to [email protected] automatically instead.

You can restrict the outgoing addresses that get relayed this way via relay_recipient_maps (you'd want this, to avoid spammers abusing it). See example config documented here. It is not supported by DMS, feature would need to be added or manually manage the config yourself.

You'll probably also need smtp_generic_maps which is what maps @example.com to @gmail.com for outgoing mail. If you want to keep the original FROM / Sender address, then you'll probably need PostSRSd I think since you'd otherwise need SPF approval from everyone sending mail to you for you to relay on their behalf.