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Re: [Nmh-workers] What should nhm do with busted Subject: lines?

2015-11-04 23:01:05
Technically ... those are legal nowadays.  See RFC 6532.  That's a
message/global message.

*blink* *blink*... Wait, what? When did *that* happen? :)

Dude, this has been discussed on this list for a few years now ... it's not
like we didn't know it was coming.  The precursor to RFC 6532, RFC 5335,
was published in 2008.

After digging into it, it looks like somebody *still* deserves to be smacked
around with a large trout, because there's no indication that that anybody
followed RFC6531 and negotiated SMTPUTF8, but just blindly spewed the UTF-8
(I've verified that at least 3 of the servers in the Received: chain do *not*
advertise the SMTP extension).  But then, this isn't my first rodeo (that
was back when Sendmail was still at 5.5mumble), so it's hardly surprising...

Yeah, when I looked at it back when this was first discussed I noticed
that I couldn't find any MTAs that offered SMTPUTP8 (although I see now
gmail does, FWIW).  I suspected that many people would just blast out
UTF-8 and MTAs would happily pass it along.  FWIW, I see that Postfix
now supports SMTPUTF8, and you can configure it to reject 8-bit characters
in email headers with strict_7bit_headers.  But the default for that is
'no', and in the Postfix documentation it says:

 Reject mail with 8-bit text in message headers. This blocks mail from
 poorly written applications.

 This feature should not be enabled on a general purpose mail server,
 because it is likely to reject legitimate email.

It seems like the bottom line is sending bare 8-bit characters in email
headers has been de facto supported for a while now (and actually up
until the last release nmh would happily do that also).

In one sense ... this isn't nmh's problem, except for the fact that we
don't deal with these messages so well right now.  But since nmh isn't
a SMTP MTA by the time we get to the message all of the transport has
been completed; we really don't have a way to tell if SMTPUTF8 has
been used or not.

--Ken

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