Question

I am opening a socket on port 119 (using idHttpServer) and it opens ok (no errors reported and i can see that the port 119 is opened by looking at netstat). But when my socket client sends a request to the server 119 port, the server does not get the request neither the client works. If i change the socket port to another one (such as 90, 80, 120) it works fine.
I guess that the socket port 119 is a SO reserved port (but theres nothing running on that port, i am sure about that). I also know that port 119 is used by news protocol (but there is no news server).
Does anyone know why i cant connect to the 119 port? The same thing happens with the 110 port (pop, but not pop server on). It is driving me crazy.

Delphi 2010
Latest indy version
Windows 2003 server enterprise edition.

Answer 1

It shall to be something in your development machine, because it is perfectly valid to use the 119 port (or any other available port) with INDY HTTP Server. Take in account it is not recommended to use ports different than 80 below the 1024 reserved ports to to that, but that’s another thing.

I made a simple test, two applications. Here are the relevant parts:

Server

dfm

object Form2: TForm2
  Caption = 'Server'
  object IdHTTPServer1: TIdHTTPServer
    Active = True
    Bindings = <>
    DefaultPort = 119
    Left = 56
    Top = 40
  end
end

Client

dfm

object Form3: TForm3
  Caption = 'Form3'
  object Memo1: TMemo
    Left = 16
    Top = 8
    Width = 185
    Height = 89
    Lines.Strings = (
      'Memo1')
    TabOrder = 0
  end
  object Button1: TButton
    Left = 207
    Top = 8
    Width = 75
    Height = 25
    Caption = 'Connect'
    TabOrder = 1
    OnClick = Button1Click
  end
  object Button2: TButton
    Left = 207
    Top = 39
    Width = 75
    Height = 25
    Caption = 'Disconnect'
    TabOrder = 2
    OnClick = Button2Click
  end
  object IdTCPClient1: TIdTCPClient
    OnStatus = IdTCPClient1Status
    ConnectTimeout = 0
    Host = 'localhost'
    IPVersion = Id_IPv4
    Port = 119
    ReadTimeout = -1
    Left = 32
    Top = 40
  end
end

pas

procedure TForm3.Button1Click(Sender: TObject);
begin
  IdTCPClient1.Connect;
end;

procedure TForm3.Button2Click(Sender: TObject);
begin
  IdTCPClient1.Disconnect;
end;

procedure TForm3.IdTCPClient1Status(ASender: TObject; const AStatus: TIdStatus;
  const AStatusText: string);
begin
  Memo1.Lines.Add(AStatusText);
end;

The result:

Dont forget to allow traffic on the firewall, for example by accepting the default windows dialog (in case of using windows firewall):