erigi on PHP is deprecated (e-mail validation)

Question

Since erigi() is deprecated in PHP 5 and I am in a need to validate an e-mail id, which function should be used? I need the format for e-mail validation such as:

<?php
function checkEmail($email) 
{
   if(eregi("^[a-zA-Z0-9_]+@[a-zA-Z0-9\-]+\.[a-zA-Z0-9\-\.]+$]", $email)) 
   {
      return FALSE;
   }

   list($Username, $Domain) = split("@",$email);

   if(getmxrr($Domain, $MXHost)) 
   {
      return TRUE;
   }
   else 
   {
      if(fsockopen($Domain, 25, $errno, $errstr, 30)) 
      {
         return TRUE; 
      }
      else 
      {
         return FALSE; 
      }
   }
}
?>

Answer 1

Use the filter_var PHP function instead:

if (filter_var($email, FILTER_VALIDATE_EMAIL)) {

}

Or, even better yet, use a RFC-compliant email address validator. As no amount of regex will encompass all the valid emails that are possible.