R=
Recipient rewriting rule set All versions
The R= delivery
agent equate specifies a rule set to be used for
processing all envelope- and header-recipient
addresses for a specific delivery agent. Mail
messages are always addressed to at least one
recipient, but there can be more. The addresses of
the recipients are given in the envelope and are
usually repeated in the mail message’s
header.[281] The envelope address is given to
sendmail in one of three
ways: as a command-line argument; as an SMTP
RCPT To:
command; or as To:, Cc:, and Bcc: headers (if the -t command-line switch
is given).[282]
Figure 20-1 shows how the R= rule set fits into the flow of
addresses through rule sets.
Figure 20-1. The flow of addresses through rule sets
There are two forms for the R= delivery agent equate. One is the
standard form, and the other is an enhanced
alternative beginning with V8
sendmail:
R=ruleset ← legal for all R=eset/hset ← legal beginning with V8
In the first case, ruleset
specifies the rule set to use in rewriting both
headers and the envelope. If that value is zero or
if the entire R=
delivery agent equate is missing, no rule set is
called.
In the second case, two rule sets can be specified.[283] One rule set is specific to the envelope, and the other is specific to headers. The envelope-specific rule set is the one to the left of the slash; the header-specific rule set is to the right (
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