Many times I get this php question; How do I use a different mail server than is mentioned in the Php.ini to send mail from a web site form?

The simple way is to have something like this included as part of the doc. By placing this at the top of the doc you can define it to your php scripts. A special note though many hosts use a internal relay server as a preferred. This is due to the fact that they force authentication in order to send mail from their mail servers. You may wish to check with your web host to make sure if this does not work. They would typically give you the name of the internal relay server that would handle this outbound mail. This would go into the field "mail.domainname.com".

ini_set('SMTP', "mail.domainname.com");
ini_set('sendmail_from', "noreply@domainname.com");