The best way of verifying an email

[eluser]Leggy[/eluser]
Well i have been fiddling with an old function recently and as many of you know checkdnsrr() doesn't work on windows servers so i decided to create an email checking function which checks the servers OS and if it is windows it uses fsockopen on port 25 to check. Here is my current function:

Code:

<?php
function check_email( $email, $rec_type = 'MX' )
{
    // Check if the domain is the correct format e.g. [email protected]
    if( !@preg_match( '/^([a-z0-9\+_\-]+)(\.[a-z0-9\+_\-]+)*@([a-z0-9\-]+\.)+[a-z]{2,6}$/ix', $email ) ) return;
    else
    {
        // Check if they included a rec type to check the server
        if( $rec_type == ( '' or null or false ) ) return true;
        else
        {
            // Seperate the username and domain to for checking
            list( $username, $domain ) = @split( '@', $email );
            
            // Check if the server is a Windows server
            if( @stristr( PHP_OS, 'Win' ) and PHP_OS != 'Darwin' )
            {
                // Check the socket (25)
                if( @fsockopen( $domain, 25, $errno, $errstr, 30 ) ) return true;
                else return;
            }
            else
            {
                // Check the DNS record
                if( @checkdnsrr( $domain, $rec_type ) == true ) return true;
                else return;
            }
        }
    }
}
?>

What would you recommend adding?

I was also considering modifying this so be able to use it in the verification class instead of its current email checker which only uses regex.