Re: Per application TCP/IP traffic filtering in Linux (sort of personal firewall)

From: aborka (aborka@hotmail.com)
Date: 04/27/02 

From: aborka@hotmail.com (aborka)
Date: 27 Apr 2002 10:51:03 -0700

John Thompson <john@starfleet.attglobal.net> wrote in message news:<slrnacl5p3.mnn.john@starfleet.attglobal.net>...
> In article <7918f6f1.0204261836.7f0e4b62@posting.google.com>, aborka wrote:
>
> > OK, here is the scenario. I have a LINUX developer machine at home
> > directly connected to the Internet.
> > Used one user login only (other than root). Running a software
> > firewall. That's it.
> > 1. I have a browser to surf the Internet on port 80 for example. Let's
> > make it Mozilla.
> > 2. I have a graphical email client to check my emails. Evolution for
> > example.
> >
> > How can I configure Linux to enable port 80 for incoming/outgoing
> > traffic for my browser but disable it for the email client?
> > Unfortunately, I was not able to figure it out, nor found any firewall
> > program, which can do it (using Firestarter for a start).
>
> Unless I'm misunderstanding something, you shouldn't have to enable port
> 80 at all unless you're running a web server (not a client like Mozilla).
> The client will open a non-privileged port to connect to port 80 *on the
> remote machine*, not yours. The same goes for email clients; they open a
> non-privileged port on your machine and connect to a privileged port on
> the remote machine.

Maybe I used the wrong terms. But the task is still the same.
So, let's say for example I do not want to enable Evolution to connect
to any remote machine on port 80, but I want Mozilla to be able to do
it.
Or, when I see that an HTML email came from my boss, I want to enable
Evolution in that one case.

Another example:
I do not want Mozilla to be able to do any ftp, even if I click on a
ftp link on a page. I want only gFtp to be able to do ftp. But not
ABCDftp or anything else.

I know these are not the perfect examples but basically this is the
functionality what I need.

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