[ILUG] Detecting a port scan attempt on my machine.

Paul J Collins sneakums at zork.net
Tue Mar 6 12:48:25 GMT 2001


>>>>> "DOC" == Donncha O Caoimh <donncha.ocaoimh at tradesignals.com> writes:

    DOC> Yup, my article on CLUG talks about this. You can make
    DOC> Portsentry act as a black hole to portscanners. They simply
    DOC> don't see the machine when it's port scanned! Some of the web
    DOC> based portscanning sites recommend changing the default from
    DOC> "deny"ing packets to "reject"ing packets which has
    DOC> implications others can tell us about..

If you use REJECT, your host will return a destination unreachable,
thus betraying its presence.  If you use DENY (now called DROP in
iptables/netfilter) it just vanishes.

-- 
"Pity has no place at my table."
      -- Dr Hannibal Lecter




More information about the ILUG mailing list