DeltaV OPC Data Access Server functional overview > DCOM Setup

Set DCOM security

On both the server and client machines, DeltaV OPC Data Access Server must have the correct properties.

  1. Run the executable file, dcomcnfg.exe.
    The Component Services window opens.
  2. In the left pane, open Component Services.
    A Computers folder appears.
  3. Open the Computers folder.
    The My Computer icon appears.
  4. Right-click the My Computer icon, and then select Properties.
  5. Select the Default Properties tab to view the default DCOM security levels.
  6. The Default Authentication Level should be set to Connect.
  7. The Default Impersonation Level should be set to Identify.

Once access is permitted, COM will check security for each call. There are two categories, AuthenticationLevel and ImpersonationLevel. The authentication level dictates how secure the communication is between the client and the server. The negotiated authentication level is the highest of client and server. It can not be RPC_C_AUTHN_LEVEL_NONE if the callee wants to know who is calling him. The impersonation level is set up by the caller for how much it trusts the callee.