The Data (Message Body) File: df
All mail messages are composed of a header and a body.
When queued, the body is stored in the df
file.
Traditionally, the message body could contain only
characters that had the high (most significant) bit
turned off (cleared, set to 0). But under V8
sendmail, with a version 2 or
higher configuration file (The V Configuration Command on page
580) the high bit is left as is until delivery
(whereupon the F=7
delivery-agent flag, see F=7 on page 764, determines
whether that bit will be stripped during
delivery).
Because the message body can contain sensitive or
personal information, the df
file should be protected from
reading by ordinary users. If the queue directory is
world-readable, the TempFileMode
option (TempFileMode on page 1097) should
specify minimum permissions (such as 0600) for
queued files. But if the queue directory is
protected by both narrow permissions and a secure
machine, the TempFileMode
option can be relaxed for
easier administration.
There is currently no plan to provide for encryption
of df
files. If
you are concerned about the privacy of your message,
you should use an end-to-end encryption package or
an encrypting filesystem (not discussed in this
book).
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