PHP overwriting "From:" header

[faraco]

Hello ALL!

We have PHP 4.3.2 running on a Windows NT4 (SP6) system.

My PHP.INI shows the following lines:

[mail function]
; For Win32 only.
SMTP= 192.168.160.4 ; our UNIX machine, running sendmail

; For Win32 only.
sendmail_from= [e-mail]

; For Unix only. You may supply arguments as well (default: "sendmail -t -i").
;sendmail_path=

When I send a message to a wrong email address, the error message returns to sendmail_from address, overwriting the address specified in headers.
Here is my code:

$myemail = "[e-mail]";  

$contactemail = "[e-mail]";

$subject = "sendmail_from test";  

$message = "According to this message headers, the From: address is ".$myemail;  

$headers = "From: ".$myemail."\r\n";

mail($contactemail, $subject, $message, $headers);

After running this script, the error message is returned to "[e-mail]".
But it should be delivered to "[e-mail]", shouldn't it?

[codeDV]

Your message would have been delivered to "[e-mail]". If this failed to be delivered then the return to sender message would have been delivered to "[e-mail]".

The truth is the From: header is not used to send the Return to Sender message. After the mail function has been used and before the message is sent, PHP uses the email address in the sendmail_from = directive of your PHP.ini file when sending the message.

When PHP connects to the SMTP server it sends the line: MAIL FROM: sendmail_from. It is then that the SMTP server sets the Return-Path: header in the email to the address used in mail from. Unfortunatly you cannot set the return path header in the mail function, as it would just be over written by the SMTP server. The only way to do it is to either change the sendmail_from directive or have your PHP script manually send the mail by connecting to the SMTP server by its self.