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    <p>I don't know enough about the application, so it's possible this can be further simplified, but I would do the following:</p> <ul> <li><p>Create one or two server processes listening on known ports (you could probably get this down to one, but if you need two, ok I'll explain how to do that).</p></li> <li><p>If you can get it down to a single server process, it can listen on both ports itself. Using the <code>select</code> call, you can have it monitor for activity on each open file descriptor. In fact, this is why I think you could do the entire thing with a single process, or a small pool of them.</p></li> <li><p>Have the client connect to the known port on the server. Having the server connect to the client will give you trouble when you get into remote networks. You can always get the server somewhere with port forwarding or in a DMZ, but you can't insist that all of your clients change their network to remove NAT, disable firewalls, or forward ports for your application.</p></li> <li><p>When the client connects, if you need multiple processes, have the servers establish as open connection to each other before forking so that you can connect them using the known port.</p></li> <li><p>If you need a separate process, use <code>fork</code> to split the processes. In the child process, you close the file descriptors that are listening on the known ports. And in the parent process, you close the file descriptors that are connected to the clients in addition to the file descriptors that are connected to the other server process.</p></li> </ul> <p>Note: this is from a linux background, but I'm pretty sure all of these functions and methods will work on windows. I'm sure someone will correct me if I'm wrong. I strongly suggest trying to use <code>select</code> to get this down to a single process which will greatly simply your coding. If you need to make better use of a multi-processor system, then go multi-threaded or have a pool of processes that trade-off the connection handling. Learning about how file descriptors work after a <code>fork</code> will simplify your coding should you need to create multiple processes.</p>
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    1. POhow to manage multiple instances of an app in server connecting with multiple clients on diff machines
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    1. COThanks for your comments. Actually process A and B are two different applications, so there's no parent/child process. No fork is used.
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    2. COyou say "Have the client connect to the known port on the server" how would this work when I have several instances of the server apps running. Each instance needs to be on a different port.
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    3. COIf it's two separate processes, you'll have at least two known ports, proc A and B. If you can't get proc B down to a single process that listens and forks off children, then for each proc B, I'd have it communicate back to proc A with it's port number that is finds open. The proc A can send this port number to the client for it's second connection.
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