Proxy program - where to start?

[KempCGDR]

Hi, I'm want to write a program (in fact two programs) to do a certain thing, but I have no idea where to start. They need to:

- Program 1 needs to be able to act as a proxy on the local computer (ie, accept traffic from programs using 127.0.0.1 as their proxy server). It needs to forward this traffic to Program 2 on the server machine.

- Program 2 needs to accept the traffic mentioned above and send it on to another proxy at a known address.

- Program 2 needs to be able to send return traffic back to Program 1 (of which there will be several computers running copies of it)

In that list there are a few things I don't know how to do (or how to find out how to do):

1) Act as a proxy for programs on the same computer.
2) Send the traffic to the program on the other machine. I think I know how to send strings and suchlike using the indy components, but individual packets aren't something I've played around with.
3) Send the traffic to a proxy
4) Deal with the traffic coming back

As to the complex steps needed just to get the traffic out to the web, it is entirely neccessary because Program 2 will be used to monitor the traffic and the final proxy is used for web traffic on the network.

So, any thoughts on how to get started?

 

[KempCGDR]

Ok, I've been playing around with the IdMappedPortTCP component, which is meant to act as a proxy that forwards to another machine. Unfortunately, if I change *any* of the settings to do with addresses/ports (ones to bind to or the mapped ones) then I get a message as soon as it is created (at runtime) saying that the address/port are already in use so the binding couldn't be done. This is even if I pick addresses that I know aren't in use on the network.

I am lost in a sea of mysterious messages.

 

[KempCGDR]

Nothing? Surely someone has to have some insight into this, or at least links to relevant stuff?