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søn, 2002-03-31 kl. 00:26 skrev Phil Pennock:
> Dude, please check which machines you're referring to. Hermes does run
> Exim.
> $ dnsmx nl.demon.net
> 10 hermes.mail.nl.demon.net
> 20 relay-2.mail.nl.demon.net
> Staff mailhub. Note that checking DNS MX for @demon.nl is not going to
> give you the customer mail-system, since @demon.nl is for
> customer-facing addresses. Things like <support@???>.
Sorry, it was late and I wasn't thinking.
;; QUESTION SECTION:
;billy.demon.nl. IN MX
;; ANSWER SECTION:
billy.demon.nl. 42300 IN MX 10 punt.mail.nl.demon.net.
billy.demon.nl. 42300 IN MX 40 relay-2.mail.nl.demon.net.
> If an MTA has accepted a mail, knowing that it's promised that it will
> handle 8-bit data, then if it talks to a second MTA which does not
> promise 8-bit support, that first MTA is responsible for checking if the
> mail is not 7-bit clean and, if so, performing the appropriate
> conversion. In the case of RFC 1652, which is the only current method
> that I know of, and the one which you cite, this means MIME conversion.
> Which is horrid. And not done by Exim. So by default, Exim doesn't
> advertise 8BITMIME. If you choose to advertise 8BITMIME when you _know_
> that the subsequent mailpath is 8-bit clean, that's not going to cause
> problems.
Why is it horrid?
My "Welcome to Demon" papers tell me to use post.demon.nl as smtp
server. That's post-*.mail.nl.demon.net. When I telnet to it port 25, I
see that it's Exim 3.3, advertising 8BITMIME. But mail to billy.demon.nl
goes via a range of punt-*, that strip 8 bit characters. So mail that i
send to other domains via this server will try 8 bit.
So you think it's o.k. to send 8bit transparent to others, but not
receive it.
> If you choose to enable it anyway ... well, that's what the original
> poster was asking about. When informed of a major source of problems,
> he wisely chose to avoid the way of recklessness.
Dunno whether it's reckless. mx1.xs4all.nl is running Sendmail 8.12 that
actually transmits 8BITMIME (I tried from an xs4all BSD machine) in the
xs4all.nl domain. Mail to billy.demon.nl gets stripped, because it goes
over punt-*, mail back to the BSD machine (also Sendmail 8bit) doesn't.
I get Norwegian characters!
I wouldn't call xs4all reckless, would you?
> When Demon's mailsystems move to Exim, they _still_ won't advertise
> 8BITMIME, since we don't know what our customers run and Exim doesn't
> convert. So the sending MTA will _still_ have to convert. The only
> difference there will be that if the sending MTA is broken and the
> recipient happens to be 8-bit clean, the sending MTA would get away with
> being broken.
But you said above that conversion was horrid :-)
> Now, if you want to change any of this, consider ways to persuade Philip
> Hazel that protocol conversion support should be added to Exim, so that
> it can at least arrange for another program to do conversion, when
> necessary. Without knowing what the performance impact of that would
> be, neither I nor my employers can make any assurance as to whether or
> not we'd use that. But you could certainly use it on your mailsystem,
> and persuade others to do so.
You know, I've become convinced that conversion is horrid. Moreover,
other major North European ISPs believe so too. They just advertise 8bit
transparent:
xs4all.nl
online.no
sol.no
telia.se
Others say that they do but probably mangle everything horribly:
hetnet.nl
aol.de
Others, of course, don't ...
Tony
> Start finding out which beers Mr Hazel is particularly fond of. :^)
Never averse to a pint.
--
Tony Earnshaw
e-post: tonni@???
www: http://www.billy.demon.nl
Telefoon: (+31) (0)172 530428
Mobiel: (+31) (0)6 51153356
GPG/PGP Fingerprint: 3924 6BF8 A755 DE1A 4AD6 FA2B F7D7 6051 3BE7 B981
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