PHP. How to check if a e-mail domain exists? - php

Question

I'd like to know how can I check if I have a valid e-mail, including the domain.
For example,
e-mails like:
email1#gmail.com, email2#hotmail.com should return true,
but e-mails like:
email3#gmal.com, email4#hotmai.com should return false.
How can we do this?
I can check if a e-mail is a valid one with filter_var($email, FILTER_VALIDATE_EMAIL), but this don't guarantee that we can send the e-mail (email3#gmal.com is a example). How can we guarantee that we have a valid domain?

Answer 1

You could create a whitelist of acceptable domains but that would no doubt leave out many valid services.
You could try to connect to the domain on the appropriate port after doing an MX dig but what if the service is down for an hour for maintenance?
The best way to determine if an email is valid is by sending a verification code and have the user click on/enter the code after receiving the email.

Answer 2

You could use CURL to check if domain exist, this option is very simple but works very well. Is fast to implement.
Check this response for well tested solution:
- https://stackoverflow.com/a/12547629/1146492
To get domain email you can use something like this:
<?php
function getDomainFromEmail($email)
{
// Get the data after the # sign
$domain = substr(strrchr($email, "#"), 1);
return $domain;
}
// Example
$email = 'the_username_here#yahoo.com';
$domain = getDomainFromEmail($email);
echo $domain; // yahoo.com
?>
And than use CURL for fast check.

Answer 3

One possible solution is to attempt to connect to the domain and see if it's successful or not:
if(fopen("http://$domain"))
{
echo "success, valid domain";
} else {
echo "failure, not valid domain";
}
Where $domain is the portion of the email address following the # symbol. (This can be obtained using regular expressions).