UDP Port Scanner

Could someone show me how to make a UDP port scanner in delphi.

I've aready made a TCP port scanner, but how would I make a UDP port scanner.

Could someone show me how this is done?
ShinezAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

GloomyFriarCommented:
Just open UDP socket instead TCP socket ;-)

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
ShinezAuthor Commented:
How Would I do this?
GloomyFriarCommented:
Ok, I'll try to explain.
Amazon Web Services

Are you thinking about creating an Amazon Web Services account for your business? Not sure where to start? In this course you’ll get an overview of the history of AWS and take a tour of their user interface.

GloomyFriarCommented:
It's impossible to scan UDP port if it just was opened.
You can determine that UDP port is opened by sending some datagram to the port only.
And if you'll be lucky you'll got an answer from the server.
But server is not obliged to answer to you if you don't know its protocol ;-)

So, if you know what server you are looking for and you know its protocol then try to send some command (according to the protocol) and wait for an answer from the server. ip-by-ip, port-by-port ;-)

Good luck.
ShinezAuthor Commented:
could you show me how this is done, have edit1 for ip and edit2 for port and for label1 to display if port is open/close.

if I wanted to check if the port is open for ut2003.

default game port is 7777, the query port is 7778.

how would I get a responce that the server is up?

please could you give some code with your answer, I don't know that much about UDP.

thxs
GloomyFriarCommented:
There is no "open" and "close" terms applying to the UDP protocol.

...
Var buff: array[0..256] of byte;
...
   UDPClient := TNMUDP.Create(self);
   UDPClient.RemoteHost := 'ut2003'; // or something like '192.168.1.15'
   UDPClient.RemotePort := 7778;
   UDPClient.LocalPort := 7777;
   UDPClient.OnDataReceived := UDPClientDataReceived;
   UDPClient.OnStatus := UDPClientStatus;
   UDPClient.OnInvalidHost := UDPClientInvalidHost;
   UDPClient.OnStreamInvalid := UDPClientStreamInvalid;
   UDPClient.OnBufferInvalid := UDPClientBufferInvalid;
...

   StrPCopy(buff, "Hello!");
   try UDPClient.SendBuffer(buff, 7);
   except;
     // Error
   end;

...
procedure TMainForm.UDPClientDataReceived(Sender: TComponent;
  NumberBytes: Integer; FromIP: String);
Var buff: array[0..256] of byte;
begin
  UDPClient.ReadBuffer(buff, NumberBytes);
end;

It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Delphi

From novice to tech pro — start learning today.