Re: OT: Honor case in reply to address

From: Ansgar Wiechers (no email)
Date: Sat Nov 21 2009 - 08:03:35 EST

  • Next message: Ralf Hildebrandt: "Re: pcre:table & client_restrictions"

    On 2009-11-21 Jerry wrote:
    > I know that this has nothing directly to do with Postfix; however, I
    > figured the fastest way to get a serviceable answer would be here.
    > I maintain a few Yahoo groups. I just received a bulletin from Yahoo
    > regarding the updating of their 'Groups'.
    > <quote>
    > Also in this release is a fix for group moderators who were having
    > issues approving pending messages via email. Moderators affected by
    > this issue were using email clients that (in violation of internet
    > standards) do not honor case in reply to addresses, meaning that they
    > would turn upper case letters into lowercase. Since the codes that
    > enable email moderation to work relied on the reply address being the
    > exact sequence of characters we were expecting, email moderation
    > commands did not work for these users. But we have now updated our
    > code in a way that will enable email moderation to work for even these
    > email clients, which should allow moderators to approve pending
    > messages and members via email once again.
    > </quote>
    > I was, perhaps incorrectly, of the opinion that case was not relevant
    > in e-mail addresses. I thought that there was an RFC that mentioned
    > this; although I cannot find one that specifically mentions case
    > folding on the reply to address.
    > Is Yahoo's claim correct or are they simply trying to cover up for a
    > problem on their end?

    Quoting from chapter 2.4 of RFC 2821:

    | Verbs and argument values (e.g., "TO:" or "to:" in the RCPT command
    | and extension name keywords) are not case sensitive, with the sole
    | exception in this specification of a mailbox local-part (SMTP
    | Extensions may explicitly specify case-sensitive elements). That is,
    | a command verb, an argument value other than a mailbox local-part, and
    | free form text MAY be encoded in upper case, lower case, or any
    | mixture of upper and lower case with no impact on its meaning. This
    | is NOT true of a mailbox local-part. The local-part of a mailbox MUST
    | BE treated as case sensitive.

    Ansgar Wiechers

    "Abstractions save us time working, but they don't save us time learning."
    --Joel Spolsky

  • Next message: Ralf Hildebrandt: "Re: pcre:table & client_restrictions"

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