saurabh.hirani:

You don't understand: You'll receive an error only if the machine sends you an error packet which makes it all the way back to your machine. The 'Connection Refused' is a message from the destination machine1 telling you to go away. No machine means there's nothing to receive the packet and send you an error result.

Why can't some other computer send you a 'Destination Unreachable' message? Well:

  1. Whose responsibility is it to do that? No one has that responsibility.
  2. How can they tell that the host doesn't exist? Since a computer doesn't have to support any network services, there's no way for a different computer on the network to tell if the computer actually exists or not.

If you require feedback, then you need to use a connection with TCP.

...roboticus

1. Usually it's the computer. Some firewalls, however, can be configured to send a 'Connection Refused' because the network administrator doesn't want that sort of inbound packet.

In reply to Re^5: udp send not reporting host unreachable errors by roboticus
in thread udp send not reporting host unreachable errors by saurabh.hirani

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