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I started a while ago to use a catch-all email address. This got me thinking, can you have a reversed catch-all address? That is to say, can one send an email with any "local-part" without generating an account for it?

[email terminology: local-part@domain.TLD]

To put up an example.

Let's say that I have set up a catch-all email address; catchall@domain.com. That would mean, that any email sent to an email address which I have not registered with my host-provider would arrive at catchall@domain.com.

Thus, I sign up to a random website, with a "non-registered" "local-part" and that email is i-do-not-exist@domain.com. This would mean that any email sent to i-do-not-exist@domain.com would be forwarded to catchall@domain.com.

Now, what happens if I want to send an email from i-do-not-exist@domain.com? The only way I know, would be to go into 'my-host-provider > emails > manage' and create an email account for i-do-not-exist@domain.com.

So, with the infinite wealth of knowledge here in SuperUser, do you have any ideas?

If this is possible, I do assume it will partially depend on which host-provider and email-client I am using.

FoxPaw
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1 Answers1

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That's really nothing special, catch-all or not. Every IMAP/SMTP mail client allows you to specify a "From:" name and address that are different from the SMTP username (when configuring an account you are asked for both separately), as functionally SMTP authentication is already separate from the identity information, so you can just do that and configure something like an "alias" in your email app. In fact, some clients such as Thunderbird even let you edit the "From:" header on the fly while composing a message.

The only question is whether your SMTP server checks the "From:" header – it may insist that the From address matches the SMTP username, or it might not. It depends on the mail provider's SMTP configuration.

(Some systems, such as Hotmail, will just quietly replace any custom "From:" name with the one from your account, but this is rare – most systems either explicitly refuse the message or don't bother checking at all.)

grawity
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