Use Errors-To: for errors V8.1 and later

Ordinarily, V8 sendmail sends notification of failed mail to the envelope sender. It specifically does not send notification to the addresses listed in the Errors-To: header. It does this because the Errors-To: header violates RFC1123. For additional information about the Errors-To: header, see Errors-To: on page 1156.

The UseErrorsTo option is available to prevent older versions of mail-reading software from failing. When set, it allows error notification to be sent to the address listed in the Errors-To: header in addition to that sent to the envelope sender.

The forms of the UseErrorsTo option are as follows:

O UseErrorsTo=boolconfiguration file (V8.7 and later)
-OUseErrorsTo=boolcommand line (V8.7 and later)
define(`confUSE_ERRORS_TO',bool)   ← mc configuration (V8.7 and later)
Olboolconfiguration file (deprecated)
-olboolcommand line (deprecated)

The optional argument bool, when missing, defaults to true (errors are sent to the Errors-To: header). If this option is missing entirely, it defaults to false (the Errors-To: header is ignored).

The UseErrorsTo option is not safe. If specified from the command line, it can cause sendmail to relinquish its special privileges.

Get sendmail, 4th Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.