Re: Wanting to hide :113

From: NewsDoug (newsdoug@Doesn'tWork.net)
Date: 01/30/03 

From: "NewsDoug" <newsdoug@Doesn'tWork.net>
Date: Thu, 30 Jan 2003 16:32:20 GMT

"Eirik Seim" <eirik@mi.uib.no> wrote in message
news:slrnb3ickq.t01.eirik@kain.mi.uib.no...
On Thu, 30 Jan 2003 12:42:28 GMT, NewsDoug wrote:
>
> And how does this 'last router' know this?
>
>It knows, because it is your router. In order for that router to
>communicate with your computer at all, it needs your computers
>hardware address. If it does not have your computers hardware
>address, it will broadcast ARP requests. If it gets no reply, it
>will consider you non-existing and return a ICMP type 3 code 1
>(commonly known as "No route to host") to whomever tried to reach
>you across the Internet.

While I agree 'my router' is aware that the PC is on or off, it seems the my
stealthed router doesn't exist to requestors and therefore the 'last router'
would be the one prior to mine (Router 0). I am using a scenario of a blind
port scan by a requestor for this example.

PC--Router 0 (stealthed)--Router 1--Router 2-- Router 3-- etc for # of hops

Router 0 understands that the PC is not present or is present by ARP response.
But the idea of stealth is that Router 0 will not respond to port requests SYN,
ACK, or RST and does not respond to ICMP, IGMP, or any communication for that
matter from the Internet. This would seem to make the definition of 'last
router' actually being Router 1 which would then signal back that Router 0 does
not exist to the requestor at the beginning of the hops. So, wouldn't Router 1
report "no such system" as Eye was referring to when a PC is offline, not "no
such port" ?

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