Verify Email Domain

/**

 * Verify the domain on the email address is at least setup with DNS

 *

 * @param  bool $is_banned   If the email has passed previous checks

 * @param  string $email     The email address to verify

 * @return bool              If the domain fails an IP check, return that it's 'banned'

 */

function kfg_is_valid_email( $is_banned, $email ) {

	if ( true === $is_banned ) {

		return $is_banned;

	}

	$email_parts = explode( '@', $email );

	$domain      = $email_parts[1];

	$host = gethostbyname( $domain );

	if ( false === ip2long( $host ) ) {

		$is_banned = true;

	}

	return $is_banned;

}

add_filter( 'edd_is_email_banned', 'kfg_is_valid_email', 10, 2 );

/**

 * Since the `edd_is_email_banned()` function only runs to the filter if there are banned emails, we need to fake it into

 * thinking there are banned emails.

 *

 * @param  array $emails Current list of banned emails

 * @return array         Returns either the banned emails, or an array with our 'fake' email address

 */

function kfg_pad_banned_emails( $emails ) {

	if ( ! is_array( $emails ) || empty( $emails ) ) {

		$emails = array( '[email protected]' );

	}

	return $emails;

}

add_filter( 'edd_get_banned_emails', 'kfg_pad_banned_emails', 10, 1 );