The behaviour of these functions is affected by settings in php.ini.
|mail.add_x_header||"0"||PHP_INI_PERDIR||Available since PHP 5.3.0.|
|mail.log||NULL||PHP_INI_PERDIR||Available since PHP 5.3.0. (PHP_INI_SYSTEM|PHP_INI_PERDIR)|
|smtp_port||"25"||PHP_INI_ALL||Available since PHP 4.3.0.|
|sendmail_path||"/usr/sbin/sendmail -t -i"||PHP_INI_SYSTEM|
Here's a short explanation of the configuration directives.
Add X-PHP-Originating-Script that will include UID of the script followed by the filename.
The path to a log file that will log all mail() calls. Log entries include the full path of the script, line number, To address and headers.
Used under Windows only: host name or IP address of the SMTP server PHP should use for mail sent with the mail() function.
Used under Windows only: Number of the port to connect to the server specified with the SMTP setting when sending mail with mail(); defaults to 25. Only available since PHP 4.3.0.
Which "From:" mail address should be used in mail sent from PHP under Windows. This directive also sets the "Return-Path:" header.
Where the sendmail program can be found, usually /usr/sbin/sendmail or /usr/lib/sendmail. configure does an honest attempt of locating this one for you and set a default, but if it fails, you can set it here.
Systems not using sendmail should set this directive to the sendmail wrapper/replacement their mail system offers, if any. For example, » Qmail users can normally set it to /var/qmail/bin/sendmail or /var/qmail/bin/qmail-inject.
qmail-inject does not require any option to process mail correctly.
This directive works also under Windows. If set, smtp, smtp_port and sendmail_from are ignored and the specified command is executed.