On Thu, Apr 17, 2008 at 7:58 AM, Kr Alfabeta <kristis / micro.lt> wrote:
>  So in conclusion there is no way to check that UDP port is working or
>  not? Maybe there is a common query which you can send by UDP and then
>  receive any response?

There is no query/response in UDP.  It's fire-and-forget.  The only
way you can get a "response" is if you control the receiving computer
and can put some code on it to fire a message back to a receiving port
on the sender after it receives a message.  Of course, in UDP there's
no guarantee that the reply will arrive...

Having once implemented a reliable multicasting protocol on top of UDP
(long story), I can say this:  don't try to treat UDP as a
connectional protocol unless you have a really, really good reason.
That's what TCP is for.

-- 
Avdi

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