Message-ID generator in PHP for mail headers.
<?php
/**
* @see http://www.jwz.org/doc/mid.html
*/
function generateMessageID()
{
return sprintf(
"<%s.%s@%s>",
base_convert(microtime(), 10, 36),
base_convert(bin2hex(openssl_random_pseudo_bytes(8)), 16, 36),
$_SERVER['SERVER_NAME']
);
}