Re: [Exim] Forgive my ignorance ...

Quoting Tony Earnshaw <tonni@???>:

> But especially with rfc1652, or has it been superceded? I can't find
> its successor.
>
> I want 8 BITMIME.
>
> Phil Pennock don't want to give it to me. His employer is my ISP. Exim
> and most other MTAs, on the contrary, do.

Exim will give you 8BITMIME if you ask it to, but it won't be rfc1652
compliant if you relay to any unknown host as you don't know if the next
hop will be 8BITMIME capable.

> Demon is NOT rfc1652 compliant.

False, Demon IS rfc1652 *compiant* by not advertising *BITMIME when it
can't do it.

> I simply have to switch ISP from Demon to xs4all.nl. To get 8BITMIME.
>
> xs4all.nl (ISP), aftenposten.no (daily), dagbladet.no (daily), bt.no
> (daily), aftonbladet.se (daily) are all rfc1652 compliant.

If all of them are compliant to rfc1652, what is the problem of Demon not
implementing 8BITMIME, all of those servers, when connecting to Demon
server will see it is not 8BITMIME capable and MUST then either convert
the mail to 7bit (via quoted-printable or base64) or bounce the mail
(which is not a good idea, you better be 8BITMIME non capable then bounce
it at relay time). The problem resides at these other server that send
invalid data at Demon.

** Quoted from rfc1652: **
If a server SMTP does not support the 8-bit MIME transport extension
(either by not responding with code 250 to the EHLO command, or by
not including the EHLO keyword value 8BITMIME in its response), then
the client SMTP must not, under any circumstances, attempt to
transfer a content which contains characters outside the US-ASCII
octet range (hex 00-7F).

A client SMTP has two options in this case: first, it may implement a
gateway transformation to convert the message into valid 7bit MIME,
or second, or may treat this as a permanent error and handle it in
the usual manner for delivery failures.
** end of quote **

If you get mail that should be 8 bit but have had it's 8thbit truncated by
Demon, it is because of the sending server non-compliance to rfc1652. Of
course, if you have a 8bit clean path all the way, that non-compliance
will not appear... but that doesn't mean the problem is with the 7bit only
capable server.

And setting Exim to advertize 8BITMIME on a relay host is rfc1652
non-compliance. If Exim only handle inbound mail on a system where the
other agents do 8bit, it's ok to advertize as you know it won't cause
problem to them. You should not send 8bit messages through Exim unless it
is via a smarthost that will do the conversion when necessary.

> > You yourself and the services you directly control do not have to
> > interoperate using the agreed upon standards if you don't want to.
> > However you have absolutely zero right to complain when other people
> > implement systems that are explicitly designed to interoperate with as
> > wide a group as possible.
>
> Rubbish (English), trash (American). "As wide a group as possible"
> implies: "The rest of the world".

Yes, and every MTA can receive 7bit messages, the MTAs that can't send
8bit messages to 7bit MTAs are those that doesn't interoperate
correctly...

> > > b: why, if all other countries in Europe sanction 8-bit smtp data,
> > > this group doesn't (see a: above).

*bit data is fined... as long as it is encoded in 7bit when transfered to
a non 8bit clean MTA.

> > 8-bit SMTP data is a lost cause with no realistic benefit. Literaly
> > everyone who needs more than 7-bit ASCII can have access to multiple
> > implemntations of MIME in almost every conceivable environment.
>
> Trouble is, they don't choose to do so.
>
> rfc1652

read it again, especially the part I quoted above...

> Many Norwegian mail servers don't serve quoted-printable, and then all
> of this is useless. Worthless.

Ah, you mean many Norwegian MTA expect every other MTA to support an
*extension* are not rfc1652 compliant when they connect to a server which
do not? What software are they all running?

Please re-read rfc1652 and do understand that not everyone has an 8BIT
environment and that you can't just throw 8BITMIME to any machine without
it advertizing that it can preserve those 8th bits. And a machine that
advertise this can't just send it to one which doesn't (as this is a sure
way the 8th bits can be destroyed). And Demon is not the only host in the
world that can't do 8BITMIME, there can be many that don't advertize it
and yet will still preserve the 8th bits, you can't count on this.

And having 8BITMIME does not guarantee you won't receive quoted-printable
or base64 encoded messages, if you want all your messages in 8bit, you
need to add some mime converter before delivery to your mailbox...



--
Patrice Fournier
pfournier@???