What is the quickest way to detect an unreachable host in Java?

Question

I would like the fastest and most accurate function boolean isReachable(String host, int port) that passes the following JUnit tests under the conditions below. Tim

Answer 1

Not sure how practical this is.

How about doing the equivalent of traceroute(tracert on windows) and once you get a success, you can proceed.

In corporate networks, I've seen ICMP(ping) blocked by admins BUT usually, tracert still works. If you can figure out a quick way to do what tracert does, that should do the trick ?

Good luck!