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Sendmail, 3rd Edition by Bryan Costales

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Name

error

Synopsis

All versions of sendmail define a special internal delivery agent called error that is designed to aid in the issuance of error messages. It is always available for use in the parse rule set 0, the localaddr rule set 5, and the Local_check and other policy setting rule sets. It cannot be defined with an M command.

Beginning with V8.7, the form for using the error agent in the RHS of a rule looks like this:

R...          $#error $@ dsnstat  $: text of error message here

In general terms, the text following the $: is the actual error message that will be included in bounced mail and sent back to a connecting SMTP host. For example, the following rule in the parse rule set 0 would cause all mail to the local user George Washington to bounce:

RGeorge.Washington       $#error 5.1.1 $: 553 George doesn't sleep here anymore

with an error message such as this:

553 5.1.1 <george.washington>... George doesn't sleep here anymore

The $@ dsnstat part when used with the error delivery agent

Delivery Status Notification (DSN, see RFC1893) provides a means for conveying the status of a message’s delivery. That status is conveyed in the form of a three-part numeric expression (so as to be easily parsed by machines). This expression is included in the “machine-readable” part of bounced messages:

success.category.detail   

Each part is separated from the others with dot characters. There can be no space around the dots. The parts are numeric, and the meanings are as follows:

success

Was the overall delivery ...

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