Re: [Fetchmail-users] UTF-8 support?

[Sergey O. <sor...@gm...>]

Matthias Andree <mat...@gm...> writes:

> Am 06.03.20 um 12:01 schrieb Sergey Organov:
>> Hello,
>>
>> Does fetchmail support UTF-8 for IMAP and POP, as described in:
>>
>> https://tools.ietf.org/html/rfc6855
>>
>> and
>>
>> https://tools.ietf.org/html/rfc6856
>>
>> ?
>
> Fetchmail is 8-bit clean, but no release in existence today sends UTF8
> commands.

Thanks, that's what I've expected.

To be honest, I don't even understand what actual problem those 2 RFCs
are to solve. I mean I don't understand why server can't just send what
it has "as is".

>
>> I get my mail using fetchmail  and recently started to receive
>> notification e-mails of the form:
>>
>> Subject: Cannot display Unicode content
>>
>> This E-mail message was determined to be Unicode-formatted
>> but your E-mail reader does not support Unicode E-mail.
> E-Mail UTF-8 is a different thing that protocol commands and responses
> being UTF-8. But it might be that your server is creating surrogate
> messages.

Do you mean: https://tools.ietf.org/html/rfc6858 ?

Dunno, but to me it looks like server rather does not create surrogate
messages.

>> Please use an E-mail reader that supports POP3 with UTF-8
>> (see https://tools.ietf.org/html/rfc6856.html).
>>
>> This can also happen when the sender's E-mail program does not
>> correctly format the sent message.
>
> What is your mail server type and address?

It's corporate server mail.javad.com and I dunno its type. Probably I
can figure through our IT team if needed.

> It might be that the server detects "client not sending UTF-8 but
> non-ASCII stuff in content" and decides "so send this warning e-mail
> instead of real content".
>
> I don't have a UTF8 server to test against apparently... so this would
> make debugging impossible.

If I get a patch, I think I can test it against the server. I guess
it should be something rather simple like sending additional
command claiming UTF-8 support? 

>
>> The original message is included as a separate attachment
>> so that it can be downloaded manually.
>>

> The list strips attachments, please send it to me again off-list,

I didn't try to include attachment and I'd rather not, as it might be
confidential.

> but I'd guess that this is actually a failure of the mail client or
> the sender's mail client.

Why? Suppose the server got proper e-mail with UTF-8 encoded headers.
Now fetchmail tries to fetch the e-mail, and server in turn tries to
ensure that it will send content that will be understood by the
requester. As fetchmail doesn't support relevant RFC indeed, server
decides support is absent and issues warning message.

Anyway, there is no other mail client by fetchmail on my side that
connects to the server, and my googling about the problem revealed that
some recent mail servers start to issue such warning e-mail indeed when
they can't detect proper UTF-8 support when server needs to present a
message with UTF-8 encoded headers to client.

-- Sergey