Name

Apparently-To:

Synopsis

If the header of a mail message lacks recipient information (lacks all of the To:, Cc:, and Bcc: header lines), sendmail adds an Apparently-To: header line and puts the recipient’s address from the envelope into the field of that line. This behavior is hardcoded into pre-V8.7 sendmail, but beginning with V8.7, it can be tuned with the NoRecipientAction option (NoRecipientAction).

The Apparently-To: header name is not defined in RFC2822. It is added by pre-V8.7 sendmail because RFC2822 requires at least one To: or Cc: header, and neither is present.

RFC2821 specifically recommends against the use of the Apparently-To: header, so that header should never be defined in the configuration file.

Get Sendmail, 3rd Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.