lib`. It's highly recommended to have sendmail available from your `PATH`. Also, the user that compiled PHP must have permission to access the sendmail binary.

Installation PHP Mail Functions

There is no installation needed to use these functions; they are part of the PHP core.

The behaviour of these functions is affected by settings in php.ini.

Mail configuration options

Name	Default	Changeable	Changelog
SMTP	"localhost"	PHP_INI_ALL
smtp_port	"25"	PHP_INI_ALL	Available since PHP 4.3.0.
sendmail_from	NULL	PHP_INI_ALL
sendmail_path	NULL	PHP_INI_SYSTEM

SMTP string: Used under Windows only: host name or IP address of the SMTP server PHP should use for mail sent with the mail() function.
smtp_port int: 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.
sendmail_from string: Which "From:" mail address should be used in mail sent from PHP under Windows. This directive also sets the "Return-Path:" header.
sendmail_path string: 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.