// Function checkMX() checks if a domain exists

        function checkMX($email,$record = 'MX') {

                list($user,$domain) = split('@',$email); // split email in user and domain

               

                if (checkdnsrr($domain,$record) == 1) return TRUE; // return true if mx record exist

                else return FALSE; // return false if not

        }

function emailCheck() {

                if($this->pibase->cObj->data['tx_powermail_sender'] && is_array($this->sessionfields)) { // If email address from sender is set in backend

                        if($this->sessionfields[$this->pibase->cObj->data['tx_powermail_sender']]) { // if there is content in the email sender field

                                if(!t3lib_div::validEmail($this->sessionfields[$this->pibase->cObj->data['tx_powermail_sender']])) { // Value is not an email address

                                        $this->sessionfields['ERROR'][str_replace('uid','',$this->pibase->cObj->data['tx_powermail_sender'])][] = $this->pi_getLL('error_validemail'); // write error message to session

                                } else { // Syntax of email address is correct - check for MX Record

                                        if( !$this->div_functions->checkMX( $this->sessionfields[$this->pibase->cObj->data['tx_powermail_sender']] )) $this->sessionfields['ERROR'][str_replace('uid','',$this->pibase->cObj->data['tx_powermail_sender'])][] = $this->pi_getLL('error_nomx'); // write error message to session

                                }

                        }

                }

        }