sendmail, 4th Edition

${dsn_notify}

The DSN NOTIFY= value V8.10 and later

When sendmail receives a message via SMTP, it can also receive information about how it should handle a bounce. That information is included as part of an sender declaration:

RCPT To:<address> NOTIFY=how

Here, the SMTP RCPT To: command specifies an envelope recipient’s address. Following that address is the keyword NOTIFY=, followed by one or more of four possible keywords: success, failure, never, and delay (see -N on page 244 for a more complete description of NOTIFY= and its keywords).

The keywords specified are made the value of the ${dsn_notify} macro. If no NOTIFY= is specified, the ${dsn_notify} macro is undefined (NULL). If multiple RCPT To: commands are issued during a single SMTP session, each command will update the ${dsn_notify} macro in turn, overwriting the prior RCPT To: command’s value.

The ${dsn_notify} macro is also given a value if the -N command-line switch (-N on page 244) is used to set the NOTIFY= keyword during mail submission.

One use for this ${dsn_notify} macro might be to log every instance when notification of success is requested. One way to do this is with a syslog map in the check_compat rule set:

LOCAL_CONFIG
Klog syslog -D -LNOTICE

LOCAL_RULESETS
Scheck_compat
R$*                     $: $&{dsn_notify} $| $1
Rsuccess $| $* $| $*    $: $(log dsn=success, recipient=$2, sender=$1 $)

Here, we declare a syslog map (syslog on page 939) with the K configuration command (The K Configuration Command on page 882) in the LOCAL_CONFIG part ...