Very Computer

>Hi all!
>I programme an Unix chat server. To log in a client uses a browser and loads
>a HTML frame page. One frame contains a java applet, another frame connects
>directly to the chat server with http://www.abc.xy:12345/. The chat server
>has now to find out that these two connections belong to one client.
>I used getpeername() to retrieve the IP adresses of the clients and to find
>out what connections belong together.
>This didn't work always, and meanwhile I know what the problem is (thanks to
>Soumen in c.p.tcp-ip): If the client uses a proxy I get different IP
>adresses. That is if I use getpeername() to get the IP adress the connection
>to the java applet returns the IP adress of the client. But the connection
>to the HTML page in the browser returns the IP adress of the proxy! With
>different IP adresses it is impossible to the server to find out that the
>two connections belong to one client.
>How can I find out that the two connections belong to the same client? Is it
>possible to get the IP adress of the client behind the proxy? I'd say it
>should be possible because there is a connection between the server and the
>client's HTML page - but how?

> >Hi all!
> >I programme an Unix chat server. To log in a client uses a browser and
loads
> >a HTML frame page. One frame contains a java applet, another frame
connects
> >directly to the chat server with http://www.abc.xy:12345/. The chat
server
> >has now to find out that these two connections belong to one client.
> >I used getpeername() to retrieve the IP adresses of the clients and to
find
> >out what connections belong together.
> >This didn't work always, and meanwhile I know what the problem is (thanks
to
> >Soumen in c.p.tcp-ip): If the client uses a proxy I get different IP
> >adresses. That is if I use getpeername() to get the IP adress the
connection
> >to the java applet returns the IP adress of the client. But the
connection
> >to the HTML page in the browser returns the IP adress of the proxy! With
> >different IP adresses it is impossible to the server to find out that the
> >two connections belong to one client.
> >How can I find out that the two connections belong to the same client? Is
it
> >possible to get the IP adress of the client behind the proxy? I'd say it
> >should be possible because there is a connection between the server and
the
> >client's HTML page - but how?

> I don't think there's any way to do this.  And even if you could, you
> wouldn't want to.  Just because two clients have the same IP address
> doesn't mean that they're the same user.  Consider a timesharing system
> like Unix, which can have many users all with the same IP address.

> The proper way to solve this problem is to pass a unique parameter to the
> Java applet that identifies the user, and have the applet pass that along
> when it connects to the chat server.  The server can remember which HTTP
> client it gave each parameter to, and use that to match up the
> corresponding chat connection.

>Thanks for your answer, Barry! But I don't understand your proposal. Surely
>I can pass a parameter to the java applet but this parameter has to be
>returned by the browser through the HTML frame connection. And how should
>this be done?
>To make it clear:

>Client                               Server
>+ java applet <------------> } the two connections belong
>+ html frame <-------------> } to the same client - how to determine?

>Currently at first the java applet gets connected. After some handshaking
>the applet gets order by the chat server to build a second connection to the
>server. It does this by changing a frame in the HTML document using
>http://www.abc.xy:12345/. I think I can't pass any parameter along this
>browser-to-chat-server connection. Or can I?

> >Thanks for your answer, Barry! But I don't understand your proposal.
Surely
> >I can pass a parameter to the java applet but this parameter has to be
> >returned by the browser through the HTML frame connection. And how should
> >this be done?
> >To make it clear:

> >Client                               Server
> >+ java applet <------------> } the two connections belong
> >+ html frame <-------------> } to the same client - how to determine?

> >Currently at first the java applet gets connected. After some handshaking
> >the applet gets order by the chat server to build a second connection to
the
> >server. It does this by changing a frame in the HTML document using
> >http://www.abc.xy:12345/. I think I can't pass any parameter along this
> >browser-to-chat-server connection. Or can I?

> You could put the parameter in the URL somewhere,
> e.g. http://www.abc.xy:12345/path/to/file?parameter.