On Tue, Feb 26, 2002 at 12:09:09PM -0500, Stephen Frost wrote:

> > > Be more specific about "with faked IP address". If the src of icmp
> > > dst port unreachable does not match the dst of the original request
> > > it will simply get dropped with no effect.

My statement above is wrong. The detemining factor is the icmp 64b payload.
So I guess '-j REJECT --fake-source x.y.z.t' can be used to fake the
originating machine. One application would be what Stephen describes below.

Ramin

> > >
> > > Ramin
> > well i was talking about Fabrice Marie's patch to cvs that allows to use
> > -j REJECT --fake-source 10.1.1.1
> > 
> > i would like Fabrice to elaborate on that a bit.
> > As you Ramin noticed, icmp not elicited by our packets, will get dropped
> > by the kernel. if we change the source ip, they will get dropped.
> 
> They will?  Is that specific to 'icmp dst port'?  I thought routers
> between the source and the destination could return ICMP errors with
> their IP address if there is not route or such...
> 
> > Or not? Please explain anyone, what is the use of this patch to REJECT
> > target.
> 
> Well, one interesting idea is a firewall bridge which doesn't actually
> have an IP address of its own being able to send ICMP error back saying
> unreachable as if it was the destiation machine... :)
> 
>       Stephen



Reply via email to