Im running exchange server 2000 with php as the server code on the website, the problem im having is using the mail function of php. Im able to receive mail from the function when I type in my exchange email address however it seems that when I try to mail out using a anything@yahoo.com, mindspring.com , or hotmail.com function returns a server error. By the way, I inserted the proper settings in the php.ini file of the send_from and the smtp server address settings. We are using php version 4.2.3.