Why do email addresses need a user name?

Question

I was thinking it would be cool to be able to have an email address that is just a domain, for example if I own bobsmith.com why can't I have bobsmith.com as my email address? Why does SMTP require a username, eg bob@bobsmith.com?

taubek · Accepted Answer

RFC 5321 defines the what that address looks like. https://www.rfc-editor.org/rfc/rfc5321#page-15

LinuxBender · Answer

Existing RFC's require an email address. What you are looking for would require a new RFC to have a default address for a domain and of course changes to all MUA's/MTA's.I think the shortest path to make something like this would just be to have an amending RFC that includes a lookup of a specific TXT record if an email address is not present. That TXT record could have a default email address for the domain.

rsclient · Answer

Historically, when the email protocol was first made [RFC 561](https://www.rfc-editor.org/rfc/rfc561) in 1973 personal computers were rare and very low power. At the time, hardly anyone owned a computer on their own.That said, might be cool, but good luck getting most apps to accept something without an @ as an email address

legrande · Answer

You could always setup a catch-all for `bobsmith.com` and then you can read every e-mail sent to that address, regardless of what username is used.