Windows NT/2000 DCOM Configuration
NOTE: These directions will open up DCOM to all users.
NOTE: These steps are used to make sure that communication can be established. After
these steps have been followed to establish communication, DCOM permissions can be
tightened to allow only the necessary users.
1) From the start menu go to run and type in dcomcnfg.
2) Distributed COM Configuration Properties Dialog.
3) Under the Default Properties Tab: Make sure that DCOM is enabled, the authentication
level is Connect and the Impersonation level is Identify.
4) Select the server from the list under the Applications Tab.
(Do this for ALL OPC Servers, as well as OpcEnum)
5) Click on “Properties”.
6) You can have your Authentication level to Default, or Connect.
7) Under the “Security” tab, select “use custom access permissions” and “use custom
8) Edit both the launch permissions and the access permissions to include “everyone”,
“interactive”, “system” and “network”.
9) Under the identity tab select “the interactive user”. Please note that services (such as
OpcEnum) will be running under “The System Account”.
10) Please repeat steps 4 through 9 for each OPC Server installed, as well as OpcEnum.
11) Under the “Default Security” tab select both the Default Access Permissions and the
Default Launch Permissions to contain: “EVERYONE”, “SYSTEM”, “INTERACTIVE”,
12) Now that this has been completed for both the Default Security Permissions, and the
Custom Security Permissions for each OPC Server we can close down DCOMCNFG.exe.
13) Please shut down and restart all OPC Servers that are to be used. That means both
those running as an application, and those running as a service.
14) To restart one running as a service please go: Start -> Run -> “Services.msc”
15) Please right click on the Server, and go “Stop”.
16) Please right click again and go “Start”, your service is now restarted and any changes to
the DCOM have been updated.
Your DCOM is now setup to accept all incoming connections.
NOTE: DCOM has limitations for connectivity when operating on
separate domains/workgroups. These steps may work but,
depending on individual networks, additional settings components may be required. Please contact OPC Support for