This would depend on your network setup - it seems unlikely that the OS would automatically refuse to route a request to there. On OS X: $ curl --connect-t

This would depend on your network setup - it seems unlikely that the OS would automatically refuse to route a request to there. On OS X: $ curl --connect-timeout 5 -v 192.0.2.1 * About to connect() to 192.0.2.1 port 80 (#0) * Trying 192.0.2.1... * Connection timed out after 5011 milliseconds * Closing connection 0 curl: (28) Connection timed out after 5011 milliseconds So your browser will likely end up trying the connection and timing out after a while.