sendmail, 4th Edition

X-Authentication-Warning:

Notification of security matters V8 sendmail

If the PrivacyOptions option (PrivacyOptions on page 1065) is declared with authwarnings, V8 sendmail inserts a special header line for possible security concerns. That header line looks like this:

X-Authentication-Warning: host: message

Here, host is the canonical name of the host that inserted this header. The message is one of the following:

Processed by user with -C file

An attempt was made by a user other than root to run sendmail with the -C command-line switch. That switch caused sendmail to read file in place of the system sendmail.cf file.

User set sender to other using -f

A user or program’s user identity used the -f command-line switch to change the identity of the sender to other (and user was not listed with the T configuration command). This can be legitimate when the user is uucp or daemon. It can also be legitimate when the user is sending to some mailing lists (Security Features on page 173). Such a warning can also indicate that someone is trying to forge mail.

User owned process doing -bs

A user or program’s user identity used the -bs command-line switch to make sendmail receive a mail message via its standard input/output using the SMTP protocol (and user was not listed with the T configuration command). This parallels network notification set up by defining IDENTPROTO when compiling sendmail and by use of the $_ macro ($_ on page 801) in Received: headers.

Processed from queue dir

A user other than ...