8BITMIME (RFC 1652) is an Extended SMTP standardized in 1994 that facilitates the exchange of E-mail messages containing octets outside the seven-bit ASCII range. Prior to the availability of 8BITMIME implementations, mail user agents employed several techniques to cope with the seven-bit limitation, including the ASCII armoring variants and UTF-7. However, each of these workarounds necessarily inflates the bandwidth of non-ASCII transmissions.
At least the following servers advertise the 8BITMIME extension:
Courier (software)
ESMTP [http://esmtp.sourceforge.net/]
Microsoft Exchange Server (versions newer than 5.5. x )
Maillennium [http://www.maillennium.com/]
Postfix (software)
Sendmail (since 6.57)
qmail (but does not translate eight-bit messages to seven-bit when relaying to non-8BITMIME peers, as is required by the RFC [http://cr.yp.to/smtp/8bitmime.html], [http://www-dt.e-technik.uni-dortmund.de/~ma/qmail-bugs.html])
As of June 2005, the following servers do not implement the extension:
Microsoft Exchange Internet Mail Service (through 5.5. x )
Exim (eight-bit clean)
Apache Software Foundation James [http://james.apache.org/] (planned)
Netscape Communications Corporation Messaging Server 4.15
=See also=
List of mail servers
RFC 3516, Internet Message Access Protocol4 Binary Content Extension