Thats where the white list comes into play.
On Thu, 2004-01-08 at 19:22, Alexander Schreiber wrote:
> On Thu, Jan 08, 2004 at 06:57:28PM +0100, Daniel Privratsky wrote:
> > Wrong.
> > 
> > 1) If you don't receive "destination unreachable" packet, you know
> > nothing about the target host yet. This is not perfect-network world.
> > There can be other fw/router anywhere in the way, killing this type of
> > icmp traffic.
> > 
> > 2) It slows scans a lot.
> 
> Only for people too stupid for doing port scans (a rare defect even
> among script kiddies).
> 
> > You can of course do scannig in parallel, but
> > don't be surprised, when you find yourself killed with no mercy by IDS,
> > after matching SYN threshold. 1000+ syns/sec form IP adress to monitored
> > system is sure ban.
> 
> Cool. Your IDS just banned the IPs of your customers mail-, web- and
> proxy-servers. Spoofing IP adresses just to mess with such automatic
> systems is easy.
> 
> Regards,
>        Alex.