PHP function fsockopen never returning false

Question

Could somebody help me with the php function fsockopen?

if I call the function like this :

$fp = fsockopen('xywqnda.com', 80, $errno, $errstr, 10);

With an unavailable host domain, it will never return false and I don't understand why!

Answer 1

Ah, you are using UDP. Your original example didn't show this. This changes things. From the PHP manual:

Warning

UDP sockets will sometimes appear to have opened without an error, even if the remote host is unreachable. The error will only become apparent when you read or write data to/from the socket. The reason for this is because UDP is a "connectionless" protocol, which means that the operating system does not try to establish a link for the socket until it actually needs to send or receive data.