Recipient’s address All versions of sendmail
qf file lists
all the recipients for a mail message. There can be
one recipient or many. When
sendmail creates the
qf file, it lists each
recipient address on an individual
R line. The form of the
R line in the
qf file looks
R must begin
the line. Only a single address can appear on each
R line. There
can be multiple
lines. Each is processed in turn.
If the colon is present and if the version of the
qf file is
greater than 0, the characters between the
R and the colon are
interpreted as flags that further define the nature
of the address:
Addresses can undergo many transformations prior to delivery. When expanding aliases, for example, the address george might be transformed into two addresses via a ~/.forward file: george@here and george@there. In this instance, george is the primary address, and the aliases are secondary addresses. If aliasing yields only a single transformation, the single new address is considered primary. Addresses that are received via an RCPT SMTP command, or on the command line, are always considered primary, as are all other recipient addressees prior to aliasing.
Recipient addresses can lead to various kinds of notification based on the nature of the DSN NOTIFY extension to the RCPT SMTP command. That notification can be either NEVER or some combination of SUCCESS, FAILURE, or DELAY. Internally, sendmail uses the absence of the latter three to imply NEVER. ...