[MlMt] MmSMTPUTF8Enabled

[Philip Paeps]

On 2016-03-03 23:26:42 (+0100), Benny Kjær Nielsen 
<mailinglist at freron.com> wrote:
> On 3 Mar 2016, at 17:42, Philip Paeps wrote:
>> So ... I finally upgraded to Postfix 3.1 with SMTPUTF8 support.  Is 
>> there something particular I should look out for in my mailserver 
>> logs if I enable the magic MmSMTPUTF8Enabled flag?
>
> You should be able to see that MailMate no longer encodes email 
> headers when they contain non-UTF8 code.

I already found at least one server that doesn't like SMTPUTF8. :)  I 
was a little surprised that when I sent a test (or more accurately 
"tëst") email from MailMate with SMTPUTF8 enabled through my server 
which supports SMTPUTF8 (now) to a third mailserver, I get a bounce 
complaining about SMTPUTF8 not being supported on the third server.  I 
would have expected my mailserver to have made appropriate noises to the 
third mailserver.  Clearly not a MailMate problem though.

The same "tëst" message does make it through Postfix and Dovecot to my 
mailbox as long as I don't try to send it across the internet. :)

> Also, when using international user or domain names MailMate should 
> provide them without puny-coding the domain names.
>
> But in general you should just look out for any problems. In 
> particular, any problems caused by MailMate behavior, but I'm also 
> interested in knowing how well it works in general. I'm sure some 
> email clients (maybe even MailMate) could have issues handling 
> unencoded email headers.

I wanted to try out my فيليب@trouble.is alias, but it turns out the 
To: field in MailMate isn't too happy about bidirectional email 
addresses.  I can type (or paste) فيليب, but it wants to put the @ 
on the left of the ف rather than the right of ب.  There seems to be no 
way to convince the To: field of that (ridiculous -- but real!) email 
address.

Amazingly, if I paste فيليب@trouble.is, the email bounces, but ... 
if I paste trouble.is@فيليب it works. :)

So I think MailMate is probably behaving mostly correctly as far as I 
can tell with an afternoon of testing.  Except for some bidirectional 
oddities.  But those might just be "Apple".  Friends in the Middle East 
are always complaining about Apple's inability to get bidi correct.  
(While I can read some Arabic/Farsi/Urdu, I'm nowhere near fluent and I 
only have the alias because it's a good way to get IDN-proponents to buy 
me beer (or culturally acceptable definitely-not-beer)!)

I think I'll need to tame Postfix on my relay to make appropriate noises 
to servers on the internet that don't speak SMTPUTF8 though.

I'll keep the option on for the time being to see what breaks.

Philip

PS: Happily, there is no "m" in my name, so I can't try out any of the 
delightful zero-width non-joiners. ;)

-- 
Philip Paeps
Senior Reality Engineer
Ministry of Information