from php.net notes about PHP mail() function:
Code: Select all
Returns TRUE if the mail was successfully accepted for delivery, FALSE otherwise.
It is important to note that just because the mail was accepted for delivery, it does NOT mean the mail will actually reach the intended destination.
IMHO theris no proper way directly using PHP to check is that $to address exist and your mail delivery was successfull.
Generally when using bounce way right way to check is it accepted by remote server it is check your mailbox.
If that $to (mail addr) is not exist on remote mail server on that remote mail server will automatically reply to you:
Can't deliver your msg.bla bla bla + a lot of tonnes server info))