Click here to Skip to main content
Click here to Skip to main content

Client/Server connection using DCOM, with anonymous access

, 8 Feb 2005
Rate this:
Please Sign up or sign in to vote.
Quick implementation of client/server connection using DCOM.


This article will explain implementing a quick client/server connection using DCOM.

Using the code

This article consists of two parts:

  • Server side implementation
  • Client side implementation

Let's start with server side implementation:

  1. Start 'New ATL COM Wizard project' with Visual Studio.
  2. Name it as TestServer.
  3. Select server type: Service.
  4. Insert new ATL object: Category-Objects, Objects-Simple Objects.
  5. Name the interface as IHello.
  6. Add method Beep().

Now, we need to turn off the authentication of DCOM server. Open TestServer.rgs from Workspace window and add the following lines just before 'TestServer.EXE':

    val AccessPermission = b '01000480300000004c000000000000001
    val LaunchPermission = b '01000480300000004c000000000000001

Open testMonitor.cpp, locate Run() function, and make it look like this:

void CServiceModule::Run()
    _Module.dwThreadID = GetCurrentThreadId();

    //This means that calls come in on a random RPC thread

    // This provides a NULL DACL which will allow access to everyone.
    hr = CoInitializeSecurity( 0, -1, 0, 0, 
         RPC_C_IMP_LEVEL_IDENTIFY, 0, 0, 0 );
    hr = _Module.RegisterClassObjects(CLSCTX_LOCAL_SERVER | 

Finally, add the following line to Beep() method and the server side is ready!!!


Now, let's implement the client:

  1. Start 'New MFC App Wizard, dialog based, name it TestClient.
  2. Insert Resource, Custom, and name it exactly TYPELIB.
  3. ID of TYPELIB resource must be 1.
  4. Open property page for TYPELIB resource and specify path to file as TestServer.tlb.
  5. Add #import "..//TestServer/testserver.tlb" no_namespace line to stdafx.h.
  6. Add includes for Afxctl.h, objbase.h and initguid.h to stdafx.h.
  7. Add _WIN32_DCOM to preprocessor definitions.

Now, we need to add the actual connection code. Add the following Connect() function to your app class:

IIHello* CTestClientApp::Connect(CString& strIPAddress, CString& strError)
    // register type library
    CLSID libid;

    CLSIDFromString (L"{55259785-1985-4DCB-B4BA-FCB7F968DFA4}", &libid);

    if (!AfxOleRegisterTypeLib(AfxGetInstanceHandle(), libid))
        AfxMessageBox("Failed to register server's type library");
        return NULL;

    CLSID clsid;
    const IID IID_IHELLO = {0xFB57F08C,0x0F91,0x4046, 
    MULTI_QI mqi = { &IID_IHELLO, 0, 0 };

    CLSIDFromString (L"{C7B7C24F-5B72-49D0-962B-FFD650BFFA2B}", &clsid);

    COSERVERINFO csi = { 0, strIPAddress.AllocSysString(), &cai, 0 };

    HRESULT hr = CoCreateInstanceEx(clsid, NULL, 
                 CLSCTX_REMOTE_SERVER, &csi, 1, &mqi);

    if (FAILED(hr))

        TCHAR szError[1024];
        FormatMessage(  FORMAT_MESSAGE_FROM_SYSTEM,
        strError = szError;
        return FALSE;

    return (IIHello*)(mqi.pItf);

From the code provided above, it can be seen that three GUIDs are needed: LIBID, CLASSID, and ITERFACEID. All of them must be taken from testserver.idl. Our connection code example is a bit hard-coded, but it allows to run the client on any machine without any registration. Server has to be registered before use. Since this is a DCOM server, it can be registered as a service or as a local server. To register the server as a service, type:

testserver /Service

To register the server as a local server, type:

testserver /RegServer

And finally, let's execute Beep() method on the remote server. To do that, let's just add a handler for the Beep button.

void CTestClientDlg::OnButtonBeep()

Hope this wasn't boring, but useful Smile | :)


  • 06/02/2005 - Initial document creation.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Vigen Dolbakyan
Web Developer
United States United States
No Biography provided

Comments and Discussions

GeneralMy vote of 3 PinmemberMichael Chourdakis22-Jul-12 1:12 
GeneralAccess is denied PinmemberFulpagar Manik10-Jun-08 0:53 
GeneralAccess Denied or class not register Pinmembersanjayrvyas27-Sep-07 2:41 
QuestionDCOM vb Client Pinmembersivaganesh_gt18-Dec-06 6:10 
GeneralGenerate & Build Proxy dll for DCOM PinmemberAshwin kumar Gurujala13-Dec-05 23:34 
GeneralRe: Generate & Build Proxy dll for DCOM PinmemberAshwin kumar Gurujala13-Dec-05 23:35 
GeneralAccess is denied PinsussFalcon eyed18-May-05 0:52 
GeneralRe: Access is denied PinmemberLayla5522-Jun-05 5:00 
GeneralRe: Access is denied Pinmemberkevinlzj8-May-06 23:00 
GeneralRe: Access is denied Pinmembershibu george20-Jul-06 20:18 
GeneralRPC-Server PinmemberNightShark15-Feb-05 1:13 
GeneralRe: RPC-Server PinmemberVigen Dolbakyan15-Feb-05 6:43 
GeneralRe: RPC-Server PinmemberNightShark15-Feb-05 12:32 
GeneralRe: RPC-Server Pinmemberskchow14-Mar-05 17:01 
GeneralRe: RPC-Server PinsussAnonymous14-Apr-05 4:58 
GeneralRe: RPC-Server PinmemberGrol214-Apr-10 4:30 
GeneralVS.NET 2003 Pinmemberbriviere29-Feb-05 6:59 
GeneralRe: VS.NET 2003 Pinmemberbriviere29-Feb-05 7:01 
GeneralRe: VS.NET 2003 PinmemberVigen Dolbakyan9-Feb-05 7:02 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

| Advertise | Privacy | Terms of Use | Mobile
Web03 | 2.8.150305.1 | Last Updated 9 Feb 2005
Article Copyright 2005 by Vigen Dolbakyan
Everything else Copyright © CodeProject, 1999-2015
Layout: fixed | fluid