| Value | Description |
| RPC_C_IMP_LEVEL _ANONYMOUS | The client is anonymous to the server. The server process cannot obtain identification information about the client and it cannot impersonate the client. |
| RPC_C_IMP_LEVEL _IDENTIFY | The server can obtain the client's identity. The server can impersonate the client for ACL checking but cannot access system objects as the client. This information is obtained when the connection is established, not on every call. |
| RPC_C_IMP_LEVEL _IMPERSONATE | The server process can impersonate the client's security context while acting on behalf of the client. This information is obtained when the connection is established, not on every call. |
| RPC_C_IMP_LEVEL _DELEGATE | The server process can impersonate the client's security context while acting on behalf of the client. The server process can also make outgoing calls to other servers while acting on behalf of the client. This information is obtained when the connection is established, not on every call. |