8BITMIME
8BITMIME (RFC 1652) is an SMTP extension 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
- ESMTP [1]
- Microsoft Exchange Server (versions newer than 5.5.x)
- Maillennium [2]
- Postfix
- 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 [3], [4])
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 James [5] (planned)
- Netscape Messaging Server 4.15
See also
- List of mail servers
- RFC 3516, IMAP4 Binary Content Extension