Hi all,
recently we've completed analysis about 8bit support in MTAs, which tested
31890 mail servers in our TLD. The results show that Exim is these days the
major MTA claiming 7bit-support only, although it's 8bit-clean for years.
Here are the figures:
total servers tested: 31890
servers responding with 220: 26704
servers announcing 8BITMIME: 22228
servers rejecting EHLO: 126
servers not announcing 8BITMIME: 4350
----------------------------------------
servers running Exim: 3701
The main reason for this is the fact, that Exim by default does not have
accept_8bitmime option enabled in the config, hence it does not announce 8BITMIME.
Although the original motivation for not enabling accept_8bitmime by default was
the lack of 8bit->qp conversion capabilities, according to the above figures the
vast majority (85% in our TLD) of "7bit" sites today are in fact 8bit-clean
Exims not announcing 8BITMIME.
While there are still legitimate situations where accept_8bitmime needs to be
disabled (e.g. when exim is configured to relay to e.g. archaic 7bit system),
having it disabled in all other cases just harms. It definitely doesn't help for
outgoing email, since MUAs typically don't honour 8BITMIME and choose encoding
based on their defaults or user preferences. As a result, Exims are already
sending 8bit emails out, no matter if accept_8bitmime is enabled or not.
Thus by enabling accept_8bitmime, an Exim site is in fact only declaring that it
can accept incoming 8bit emails from the internet and relay them as such to
configured peer MTAs. Hence it would be of great help, if Exim sites enable
accept_8bitmime unless they positively know they're acting as inbound relay for
some legacy 7bit MTA.
Thanks & kind regards,
--------------------------------------------------------------------------
---- ----
---- Marian Ďurkovič network manager ----
---- ----
---- Slovak Technical University Tel: +421 2 571 041 81 ----
---- Computer Centre, Nám. Slobody 17 Fax: +421 2 524 94 351 ----
---- 812 43 Bratislava, Slovak Republic E-mail/sip: md@??? ----
---- ----
--------------------------------------------------------------------------
