Re: Bypassing firewall

[Cliff Rayman <cliff () genwax com>]

yes. this is very possible and fairly trivial for any programmer
who knows how to write networking code.

cliff rayman
genwax.com

Mailing Lists wrote:

> Hi!
>
> Back where I work, we are using a firewall the blocks everything coming in,
> and gives internal users permission to use the www, ftp, pop and mail
> ports.  (no icq, no aol, no nothing else).
>
> But I overheard one of my users bragging that it bypassed the firewall
> using two linux machines doing port redirection.
>
> I did a little research on this and the most plausible way I found is that
> he is running a linux inside the firewall which grabs everyhing on a
> certain port (let's say the icq server port), then forward it through port
> 80 to another linux box outside the firewall which make the actual call to
> the icq server on the right port.  Is that possible?  Is there any other
> alternatives he can be using?
>
> btw, I don't know what the firewall used is, I'm the sysadm for my
> division, but we are using the corporate firewall.
>
> Thanks!