I know there are lots of RFCs that changed how an email can be made. However, most of the RFCs don't apply to for example outlook.
First of all, what are RFCs exactly? And why don't for example outlook has all RFCs applied?
For example, if I try to make a mail at outlook called
email@example.com, it will give me an error it has to start with a letter. HOWEVER:
isemail.info, it tells me the email is valid.
The same goes for
firstname.lastname@example.org, it gives an error, but on
isemail.info it says
The email address tested was email@example.com The general result is: Address is valid The specific diagnosis is: Address is valid. Please note that this does not mean the address actually exists, nor even that the domain actually exists. This address could be issued by the domain owner without breaking the rules of any RFCs.
Now, my second question is: if I would for example buy a VPS and setup an email server, how would I make emails like
My last question is about the second part (after the
isemail.info, this email is valid:
The email address tested was example@~example.com The general result is: The address is only valid according to the broad definition of RFC 5322. It is otherwise invalid. The specific diagnosis is: Address is RFC 5322 compliant but contains domain characters that are not allowed by DNS
However, I never have seen a domain like
~example.com. I assume it'd be only for local usage, but I'm not entirely sure as I've got barely any server and this kind of stuff knowledge.