On Friday 05 July 2002 00:45, christophe barb� wrote:
> On Fri, Jul 05, 2002 at 08:35:53AM +1000, George Vieira wrote:
> > Yes I've found that some user space programs can see stuff before
> > iptables.. tcpdump too I think...
>
> Yes it sounds logical for tcpdump or tools like that (which pass the
> interface in promiscuisious mode) to see everything. I was not expecting
> the same from a unprivileged app like gkrellm.
> It is stil unclear for me what is the data processing path.
>
> Has someone a clear picture of the packets path ?

It is no problem to open a socket and receive a copy of all raw packets 
before they get to the kernel iptables modules. See "man 7 packet" for 
details.

I believe this is how tcpdump does it too.

Jan Humme.

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