//Checking if a TCP port is Open using Delphi and Winsocks

uses

  Winsock;

 

function PortTCP_IsOpen(dwPort : Word; ipAddressStr:AnsiString) : boolean;

var

  client : sockaddr_in;

  sock   : Integer;

 

  ret    : Integer;

  wsdata : WSAData;

begin

 Result:=False;

 ret := WSAStartup($0002, wsdata); //initiates use of the Winsock DLL

  if ret<>0 then exit;

  try

    client.sin_family      := AF_INET;  //Set the protocol to use , in this case (IPv4)

    client.sin_port        := htons(dwPort); //convert to TCP/IP network byte order (big-endian)

    client.sin_addr.s_addr := inet_addr(PAnsiChar(ipAddressStr));  //convert to IN_ADDR  structure

    sock  :=socket(AF_INET, SOCK_STREAM, 0);    //creates a socket

    Result:=connect(sock,client,SizeOf(client))=0;  //establishes a connection to a specified socket

  finally

  WSACleanup;

  end;

end;