What does the -f flag mean in the fifth parameter in the PHP mail function?

Question

Thanks in advance

Jon

Answer 1

From http://www.browardphp.com/php%5Fmanual%5Fen/html/function.mail.html:

The *additional_parameters* parameter can be used to pass additional flags as command line options to the program configured to be used when sending mail, as defined by the sendmail_path configuration setting. For example, this can be used to set the envelope sender address when using sendmail with the -f sendmail option.

The user that the webserver runs as should be added as a trusted user to the sendmail configuration to prevent a 'X-Warning' header from being added to the message when the envelope sender (-f) is set using this method. For sendmail users, this file is /etc/mail/trusted-users.

Answer 2

The fifth parameter is for sending command line flags to the server that actually handles sending the email. So not knowing what that really means, I did a google search and found a list of command line options for command line options for sendmail.

If I had to guess, not based on that page but on almost all other sites that mention that option in passing, it's for setting the "from" header at the server level rather than at the Header level. So you'd do

  mail($stuff, $junk, $blah, $headers, '[email protected]');