Set unquoted space replacement character |
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Some mailer programs have difficulty handling addresses that contain
spaces. Such addresses are both illegal under RFC2821 and RFC2822 and
subject to gross misinterpretation. For example, the address:
John Q Public@wash.dc.gov decidedly not kosher is viewed by some MUA programs as being composed of three separate
addresses: John, Q, and
Public@wash.dc.gov. To prevent this
misinterpretation, such MUAs usually either quote the user portion or
escape each space with a backslash:
"John Q Public"@wash.dc.gov quoted
John\ Q\ Public@wash.dc.gov escaped The BlankSub option is intended to handle an
address that contains internal spaces, and is
neither quoted nor escaped. For
sendmail a space is any character defined by the
C-language library routine isspace(3).
Most sites use a . (dot or period) or an _ (underscore) character to
replace unquoted space characters. That is, they declare the
BlankSub option as one of the following:
O BlankSub=.
O BlankSub=_ Feeding the address: John Q Public@wash.dc.gov through sendmail with the option
BlankSub set to a dot yields:
John.Q.Public@wash.dc.gov The forms of the BlankSub option are as follows: O BlankSub=char configuration file (V8.7 and later)
-OBlankSub=char command line (V8.7 and later)
define(`confBLANK_SUB',char) mc configuration (V8.7 and later)
OBchar configuration file (deprecated)
-oBchar command line (deprecated) The argument char is of type
character and is a single character. The
default, if this option is omitted or if the
char argument is omitted, is that an
unquoted space character is replaced with a space character (which
does nothing to correct the problem). The default for the
mc technique is the dot (.) character.
Note that old-style addresses are delimited from each other with
spaces rather than commas. Such addresses can be wrongly joined into
a single address if the char is other than a
space. Acceptance of such old-style addresses is determined by the
setting of the OldStyleHeaders option (OldStyleHeaders).
Also note that this BlankSub option can also be
used when tokenized addresses are reassembled (see Section 18.3.3).
The BlankSub option is not safe. If specified from
the command line, it can cause sendmail to
relinquish its special privileges.
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