I'm building a PHP/MySQL driven website for my department at work (installed via XAMPP). I need to be able to send mail to outside e-mail addresses (e.g., Yahoo, Hotmail, etc.) using the PHP mail() function. As I see it I have to solutions:

1. Configure the SMTP directive in php.ini to the server running at my work.

2. Configure/run a mail server that can send e-mails outside of localhost (I'm trying Mercury because it comes installed with XAMPP).

Here are problems I've come up against:

1. I took a guess at our SMTP server name, and when calling PHP mail(), I get the error

   SMTP server response: 530 5.7.1 Client was not authenticated

   I can't be sure, however, the SMTP name is correct (I can't get help from our IT guys because of politics).

2. I have tried to use mercury mail. Mercury seems to be picking up the request, but it doesn't want to forward the e-mail to the outside. I keep getting a Temporary error 240 (temporary MX resolution error).

I've searched high and low but still can't find a definitive answer on how to send e-mails outside of localhost.

Any help is greatly appreciated.