Steve Atkins wrote: >> Exim doesn't downgrade. It doesn't advertise 8bitmime either, by default. >> If you switch on 8bitmime advertising, it still doesn't downgrade. I >> think it just tries to deliver the mail as 8bit, regardless of what the >> receiving MTA does. I think postfix and sendmail do the same, but I'm not sure. > > Exchange advertises 8bit and then bounces the mail if it tries to forward it > to a server that doesn't advertise 8bit. > > This (entirely RFC valid yet completely broken) behaviour has bitten me > a couple of times.
+1 If everyone (mail transport/mail handlers) just followed the basic mail networking principle of: Thou should not touch passthru mail (except for network traces) We would not be having these "side" issues today. There are legit reasons for transformations but mainly at the final destination (local routing). The 8BITMIME thing is ideal to tell MUA/MTA (at the Interactive Level) what is not acceptable at the MSA. So if the USER has 8bit enable in his UI, then he can switch it to 7bit compatible format. But its create problems when there is a "Mind Guessing" game between intermediaries. > I'm not sure any of this affects DKIM much, other than "Hey, look! Yet > another way DKIM signatures might get removed in transit!". The only solution I see for DKIM is to use Target/Path dependency methods, but in principle, intermediaries need to refrain from thinking they know better for downlinks. hmmm, perhaps "DKIM Scouts" :) -- Hector Santos, CTO http://www.santronics.com http://santronics.blogspot.com _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html