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>DCOM/RPC uses several ports in a predetermined range ((by default, DCOM is free to use any port over 1024) to communicate between machines. To connect to a COM server over the internet, and through a firewall, a network administrator has to open this range of ports in the firewall. The average corporate firewall only has openings in specific ports to allow for specific types of Application Layer traffic : port 80=HTTP, port 443=SSL, port 21=FTP, port 25=SMPT, etc. You can configure DCOM on the server to use a different then default range of ports, but changing these changes the port for all COM servers on that machine, and the registry entry changes require a reboot for the change to take affect. You can find out a lot about this mess by searching MSDN on DCOM and firewall.
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>I would like to again, visit the COM/Firewall argument. I still think this argument is w/o merit. For example, let's says that on the server, I have a web app powered by COM components that serve up HTML/XML. How do firewalls become an issue? Or, are you talking about scenarios where you have COM Components on the client talking with COM Components on the server? If this is the case, I suppose the COM/Firewall argument has merit. However, I would submit that is a risky scheme even over a LAN, let alone the public internet.
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>I still have to scratch my head. For 2.5 years, MS was pushing WinDNA and COM Components as THE way to build scaleable applications that could be deployed on a LAN or the Web. And now, all of that is suddenly bunk.
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>Your thoughts....
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PMFJI, I think the comparison is DCOM versus .NET Web Services. As Erik mentioned, it may be impractical to access DCOM components through a firewall. My understanding is that .NET contains the infrastructure to access remote web services just like any other object. All of the SOAP and XML stuff is handled internally and seamlessly on the client and the server. Since the communication is performed over http, there are no firewall issues. I know VFP can build Web Services, but I'm not sure how much will be provided for us on the client side.