AOL recently made an adjustment to their email delivery system with new policies that are resulting in email from PHP scripts being blocked. This effects Apache virtual servers that use generic users when sending mail (nobody@, username@, root@, apache@, etc.) and thankfully, only requires a simple fix : the use of -F.

AOL can do whatever they want, its their network. Recently, however, they made an adjustment to what email they accept from outside sources that utilize PHP. What is even more interesting is that they haven't made the adjustment public - it was only through analysis of the logs and subsequent calls with the tech center that the new policy was uncovered. It is assumed it is an effort to combat spam from entering their network.

This has implications for PHP scripts that send the user communication. All scripts will need to be adjusted to add a valid email address to the 'Return-To' header. To do so, the '-F' modifier is used in the format: '-F valid@emailaddress.xxx'

PHP's mail function allows the addition of 'additional paramaters' (http://us3.php.net/manual/en/function.mail.php [3]) that make it super easy.

So, if AOl users aren't getting email from your PHP scripts, add the -F flag (with a valid email address) and consider your problem solved..