[FIXED] How can the email sender reply address say "do not reply"?

Issue

Today I registered myself on Pinterest.com with my Yahoo account. After registration I got an email for email validation, at the bottom of the email this message was showed by Yahoo:

Sender reply address says do not reply

and I could also hide this message, I mean it was not in the body of email.

Here is screenshot of my email: http://imgur.com/ke95B

My question is:

How can I use this option when I use 'PHP PEAR' or default mail() function?

Solution

yahoo parses the reply-to header. set a header like this:

Reply-To: noreply@example.com

replace example.com with your sender domain.

it should work with either mail() (see example by Zac) or Pear

[....]
$headers["Reply-To"]="noreply@example.com";
$mail_object->send($recipients, $headers, $body); 

no-reply instead of noreply works as well. Your email from pinterest.com for example has a header Reply-To: no-reply@pinterest.com

Answered By - Gryphius

Answer Checked By - Cary Denson (PHPFixing Admin)