Install Drupal SMTP authentication support module

# install SMTP Authentication Support
http://drupal.org/project/smtp

download
http://ftp.drupal.org/files/projects/smtp-6.x-1.0-beta4.tar.gz
extract
copy smtp /var/www/sites/all/modules

# install PHPMailer
#http://phpmailer.worxware.com/
#http://sourceforge.net/projects/phpmailer/files/phpmailer%20for%20php5_6/

download phpMailer v2.3 (NOT 5.x)
http://downloads.sourceforge.net/phpmailer/phpMailer_v2.3.tar.gz
extract
rename phpMailer_v2.3 to phpmailer (LOWERCASE!)
copy phpMailer/ /sites/all/modules/smtp/

# Configure
# Enable the SMTP Authentication Support module
Administer > Site building > Modules page
/admin/build/modules
check: SMTP Authentication Support

# Fill in required settings
Administer > Site configuration > SMTP
/admin/settings/smtp

Installationsoptionen
Turn this module on or off: On

SMTP server settings
SMTP server: smtp.YOUR_DOMAIN.COM
SMTP port: 465
Use encrypted protocol: Use SSL

SMTP Authentication
Username: info@YOUR_DOMAIN.COM
Password: YOUR_PASS

# LINKS
# http://drupal.org/project/smtp
# http://phpmailer.codeworxtech.com/