Sun Microsystems Sun Workstation 100U System Manager's Manual page 320

SENDMAIL
&
1.3.4. Queuelnl
tor
retranamla.loD
If the mailer returned an status that indicated that it might be able to handle the
mail later,
ecndmtJil
will queue the mail and try again later.
1.3.i. Return
to
.ender
If errors occur during processing, BcndmtJiI returns the message to the sender for
retransmission. The letter can be mailed back or written in the file "dead.letter" in the
sender's home
directory~.
2.4. Me.lage Header Ed.ltlnl
Certain editing or the message header occurs automatically. Header lines can be
inserted under control of the configuration file. Some lines can be merged; for example, a
"From:" line and a "Full-name:" line can be merged under certain circumstances.
1.5. Configuration FUe
Almost all configuration inrormation is read
at
runtime from an ASCII file, encoding
macro definitions (defining the value of macros used internally), header declarations (telling
send mail the rormat or header lines that it will process specially, i.e., lines that it will add
or reformat), mailer definitions (giving information such as the location and characteristics
or each mailer), and address rewriting rules (a limited production system to rewrite
addresses which is used to parse and rewrite the addresses).
To improve performance when reading the configuration file, a memory image can be
provided. This provides a "compiled" rorm of the configuration file.
3. USAGE AND IMPLEMENTATION
3.1. Argument.
Arguments may be flags and addresses. Flags set various processing options. Follow-
ing Hag arguments, address arguments may
be
given, unles8 we are running in SMTP
mode. Addresses rollow the syntax in RFC822 [Crocker82) for ARPANET address for-
mats. In brief, the format is:
(1) Anything in parentheses is thrown away (as a comment).
(2)
Anything in angle brackets ("< >") is preferred over anything else. This rule imple-
men ts the ARPANET standard that addresses of the form
user name <machine-address>
will send to the electronic "machine-address" rather than the human "user name."
(3) Double quotes (" ) quote phrases; backslashes quote characters. Backslashes are
more powerful in that they will cause otherwise equivalent phrases to compare
differently - ror example,
U8fr
and
"u8fr"
are equivalent, but \
UBer
is different rrom
either of them.
Parentheses, angle brackets, and double quotes must be properly balanced and
nested. The rewriting rules control remaining parsing!.
?obviously, if the site giving the error is
no~
the origina.ting site, the only rea.sonable option is to mail back to the
sender. Also, there are many more error disposition options,
bu~
they only eired the error message - the "retul1l to
sender" function is always handled in one of these two waJl.
ar>isclaimer:
Some special processing is done after rewritinllocai namesj
Bee
below.
Verllon 4.1
DRAFT Last Mod 8/10/83