How to validate email address by domain using PHP? - php

Question

I want to validate the e-mail domain using php, because some users trying to submit contact form using dummy email ids like: aa#bb.com

Answer 1

TRY with checkdnsrr extract the domain name from the email address and pass to the checkdnsrr.
Returns TRUE if domain name are found; returns FALSE if no domain name
were found or if an error occurred.
$domainname = "domain.com";
checkdnsrr($domainname , "A");

Answer 2

If you only want to validate the syntax of the domain name section you could split the email on the # and run this regex on the second part (after running it through the idn_to_ascii() function for intenational domain names):
/
^
(?(DEFINE)(?<part>(?:xn--)?[a-z\d](?:[a-z\d-]*[a-z\d])?))
(?(DEFINE)(?<subpart>(?:xn--)?[a-z\d_](?:[a-z\d_-]*[a-z\d])?))
(?:(?&subpart)\.)*
(?&part)
(?:\.[a-z]+|\.xn--[a-z\d]+){1,2}
$
/xigm
https://regex101.com/library/PAKVdK

Answer 3

You will need to check if there is a MX record for that domain.
Consider this script in addition to you regex validation
https://davidwalsh.name/php-email-validator
Be aware that this will not 'really' validate emails completely. User could be invalid.

Answer 4

If you don't want to go through all the hassle of doing the validations by yourself, just use the free API plan from MailboxValidator.
They have some sample codes to help you with integration.
http://www.mailboxvalidator.com/api-single-validation
<?php
$apiKey = 'Enter_License_Key';
$params['format'] = 'json';
$params['email'] = 'Enter_Email';
$query = '';
foreach($params as $key=>$value){
$query .= '&' . $key . '=' . rawurlencode($value);
}
$try = 0;
do {
////////////
//For https request, please make sure you have enabled php_openssl.dll extension.
//
//How to enable https
//- Uncomment ;extension=php_openssl.dll by removing the semicolon in your php.ini, and restart the apache.
//
//In case you have difficulty to modify the php.ini, you can always make the http request instead of https.
////////////
$result = file_get_contents('https://api.mailboxvalidator.com/v1/validation/single?key=' . $apiKey . $query);
} while(!$result && $rty++ < 3);
$data = json_decode($result);
print_r($data);
?>