[Users] Address book defaults to lower case

[Brian Morrison]

On Wed, 22 Mar 2017 11:55:35 +0100
Andrej Kacian wrote:

> 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
> RFCs).
> 
> RFC 2821[1] 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-
>    sensitive.
> 
> Arguably, "MUST" takes precedence over "SHOULD".
> 
> 1. https://tools.ietf.org/html/rfc2821
> 
> Regards,

And there's the problem, you can do the right thing and still be wrong.

-- 

Brian Morrison