我不能在我的主机上使用Paypal IPN,如何解决这个问题?

I'm testing paypal ipn for a website I am building, but it fails when I try to validate the ipn. In particular this line doesn't work:

$fp = fsockopen('ssl://www.sandbox.paypal.com', 443, $errno, $errstr, 30);

the check if (!$fp) fails (fp is false). I assume it can't connect. Why this?

Update

I discovered my hosting solution doesn't support ssl, in fact I get:

Warning: fsockopen() [function.fsockopen]: unable to connect to ssl://www.sandbox.paypal.com:443 (Unable to find the socket transport "ssl" - did you forget to enable it when you configured PHP?)

Is there a way to get over this without going for another hosting solution?

You don't have to use SSL (though Paypal highly recommends it.)

$fp = fsockopen('www.paypal.com', 80, $errno, $errstr, 30);