Re: Port function and scanning



Sebastian G. <seppi@xxxxxxxxx> wrote:
Volker Birk wrote:
number). Port scanners are more seldomly used for UDP, because there is
no algorithm for this case for UDP.
There is.
no reply -> open or filtered
Wrong. No reply: open or closed.
The Nmap documenation and the real world systems' behaviour tell something
different.

That may be your view.

From RC 792:
| The Internet Protocol is not designed to be absolutely reliable. The
| purpose of these control messages is to provide feedback about
| problems in the communication environment, not to make IP reliable.
| There are still no guarantees that a datagram will be delivered or a
| control message will be returned.
Is that your argument of a misguided quote?

I fear, you just don't understand.

ICMP has message codes and subcodes, which are essentially similar to ports.
No, they aren't. ICMP is a messaging protocol using IP packets, and the
message codes have nothing to do with a port concept.
They aren't used directly for multiplexing, however this is done by
providing a part of the initial IP packet - which tells the host to which
packet the reply belongs.

Strange view.

I cannot see any argument in your posting which persists.

Yours,
VB.
--
"Es muss darauf geachtet werden, dass das Grundgesetz nicht mit Methoden
geschützt wird, die seinem Ziel und seinem Geist zuwider sind."

Gustav Heinemann, "Freimütige Kritik und demokratischer Rechtsstaat"
.



Relevant Pages

  • Re: Port function and scanning
    ... no algorithm for this case for UDP. ... | purpose of these control messages is to provide feedback about ... die seinem Ziel und seinem Geist zuwider sind." ...
    (comp.security.firewalls)
  • Re: Port function and scanning
    ... The Nmap documenation and the real world systems' behaviour tell something ... | The Internet Protocol is not designed to be absolutely reliable. ... | purpose of these control messages is to provide feedback about ... Taking packet loss into account, ...
    (comp.security.firewalls)