I'm struggling with this issue for months now. I have a simple website wich has a "Get price quota" php form that interested visitors can use to ask for prices.
The PHP form sends an email to the admin using PHP's "mail". Everything works fine with Google, Hotmail, etc EXCEPT, I get my email rejected all the time from Yahoo recipients. Every two or three months I have to get my dedicated IP changed and the hosting company to make unblacklisting requests because emails sent back to the customers bu the admin using email accounts on the same server\domain are rejected. Weird or not, not all of them are rejected.
I went through all info and tips I could find about securing my form, checked the logs to see if somehow my domain\website is used for spam, I have DKIM enabled, etc, nothing works, I know Yahoo has bad problems but I wonder if there is another way to send emails from forms, small amounts, max 100 per month.
I'm going to post my php email script below, please tell me if there is something wrong that could cause Yahoo to blacklist my domain or is it just Yahoo.
//Secure The Submitted Data
$quoteFirstName = stripslashes($_POST["quoteFirstName"]);
$quoteLastName = stripslashes($_POST["quoteLastName"]);
$quoteEmail = stripslashes($_POST["quoteEmail"]);
$quoteDetails = stripslashes($_POST["quoteDetails"]);
$quoteProduct = stripslashes($_POST["quoteProduct"]);
$quoteTel = stripslashes($_POST["quoteTel"]);
$mailtolink = '<a href="mailto:' . $quoteEmail . '">' . $quoteEmail .'</a>';
//Build The Email To The Admin
$to = "orders@mydomain.com";
$subject = "Price quota request";
$theEmail = "$quoteFirstName $quoteLastName <br /> $mailtolink <br /> Telephone $quoteTel <br /> Price quota for <br /> - $quoteProduct.<br /> Additional info: $quoteDetails";
$headers = "MIME-Version: 1.0" . "
";
$headers .= "Content-type: text/html; charset=iso-8859-1" . "
";
$headers .= "From: " . $quoteEmail . "
" . "Reply-To: " . $quoteEmail . "
" . "X-Mailer: PHP/" . phpversion();
mail($to, $subject, $theEmail, $headers);