Which ones? In RFC 5322 every address contains an addr-spec at some point, which in turn must include an @. RFC 6854 does not seem to change this. Or did I misread something?
EDIT: I’M DUMB I THOUGHT YOU MEANT A LITERAL “.” , that regex is indeed correct.
Original:
This is a valid address: user.name@[IPv6:2001:db8:1ff::a0b:dbd0]
Relevant spec: https://www.rfc-editor.org/rfc/rfc5321#section-4.1.3
And you all doubted me… :P
Edit: Wait, I also don’t think local-part even needs a “.” in it? user@domain.com should be valid as well.