PHP Check is Google Mail

<?php

/**
 * @author yuda KLN
 * @copyright 2018
 */

echo isGmail('email@domain.com') ? 'google mail' : 'not';

function isGmail($email)
{
    if ( filter_var($email, FILTER_VALIDATE_EMAIL) )
    {
        $domain = explode('@',$email)[1];
        
        $hosts = array();
        
        getmxrr($domain, $hosts);
        
        foreach( $hosts as $h )
        {
            if ( strpos(strtolower($h), 'google.com') )
            {
                return true;
            }
        }
    }
}
?>