[Users] Address book defaults to lower case
andrej at kacian.sk
Wed Mar 22 11:55:35 CET 2017
On Wed, 22 Mar 2017 10:11:25 +0000
Brian Morrison <bdm at fenrir.org.uk> wrote:
> On Wed, 22 Mar 2017 10:34:06 +0100
> wwp wrote:
> > I can't believe a server wants capitalized names in email addresses
> > (or case sensitiveness in general). Would you show us the error
> > thrown by this server?
> Actually folks, the local part of the address before the @ should have
> case preserved, there are people who do use capitalized addresses in
> this way.
You are both correct and incorrect (as is frequently the case with
RFC 2821 manages to contradict itself. In section 2.4, it says:
[...] The local-part of a mailbox
MUST BE treated as case sensitive. Therefore, SMTP implementations
MUST take care to preserve the case of mailbox local-parts. Mailbox
domains are not case sensitive. In particular, for some hosts the
user "smith" is different from the user "Smith". However, exploiting
the case sensitivity of mailbox local-parts impedes interoperability
and is discouraged.
Then later, in section 4.1.2:
While the above definition for Local-part is relatively permissive,
for maximum interoperability, a host that expects to receive mail
SHOULD avoid defining mailboxes where the Local-part requires (or
uses) the Quoted-string form or where the Local-part is case-
Arguably, "MUST" takes precedence over "SHOULD".
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