DCOM Over the Internet

Since DCOM is an inherently secure protocol, it can be used without being encapsulated in a virtual private network: DCOM applications can simply use the cheap, global TCP/IP network. Most companies do not provide direct Internet access to their desktop computers. All but some dedicated server machines are hidden behind a firewall that typically consists of protocol-level (port-based) and application-level (proxy servers) filters. DCOM can work well with both classes of firewalls:

• DCOM uses a single port for initiating connections and assigns a configurable range of ports to the actual components running on a machine (actually one port per process. See the "DCOM Architecture" White Paper for details.)
• Application-level proxies can easily be built. They can be either generic (forwarding configurable DCOM activation and method calls) or application-specific.
• Server administrators can also choose to tunnel DCOM through HTTP, effectively bypassing most of today's firewalls.

With this range of options, DCOM-based applications can use the Internet for private connectivity within a company, private communication with external customers and partners, and massive public connectivity to any client in the world. In each of these scenarios, DCOM provide flexible security whenever it is needed.