Mailing from [email protected] using Gmail, but I don't have SMTP

Question

I own several domains where I don't have separate mailboxes or mail user accounts. To receive mail, I've just setup a catch-all for such a domain that redirects to a generic address elsewhere.

Now, I want to add [email protected] as my address in Gmail (as an alias), so I can send mail using that as From-address. In the past I could simply add it, click a confirmation link, and done.

However, it seems that Gmail demands an SMTP server + user account for that domain!? I don't have that. And even if my domain would come with an SMTP server, I still don't have a mailbox or user account (since I only use email forwarding on that domain).

How do I setup Gmail so I can send mails from my custom mail address, which I do own, but for which I don't have an SMTP server or account?

Answer 1

This question has been answered here, but I'm unable to close it because of the bounty.

In short, you may use Gmail's SMTP server for your alias address, as long as you have enabled two-factor authentication.