Gentoo Archives: gentoo-security

From: Michael Milverton <camel77@×××××××××××.au>
To: gentoo-security@l.g.o
Subject: Re: [gentoo-security] firewall suggestions?
Date: Thu, 08 Jan 2004 15:11:56
Message-Id: 1073573561.4027.8.camel@wizard.home.net
In Reply to: Re: [gentoo-security] firewall suggestions? by Oliver Schad
1 Okay, many people believe that to hide your computer is good, it is what
2 many Internet security sites say. Could you elaborate on why it isn't
3 good to try to hide your computer.
4
5 Thanks
6 On Thu, 2004-01-08 at 20:27, Oliver Schad wrote:
7 > Am Donnerstag, 8. Januar 2004 13:06 schrieb mir gonzalo:
8 > > 1/8/04 8:50 AM, Oliver Schad escribio:
9 > > > Am Mittwoch, 7. Januar 2004 23:05 schrieb mir Mark Hurst:
10 > > >> It's much better to have a firewall than just have ports not open.
11 > > >> Even though a port is not open it can reveal the presence of your
12 > > >> machine by the manner in which the IP stack responds to a connection
13 > > >> attempt. Using a firewall you can drop those packets, making all
14 > > >> your closed ports invisible.
15 > > >
16 > > > If you want to invisible, the next router to you have to send an ICMP
17 > > > packet with "host unreachable". If you say nothing anybody with some
18 > > > brain between his ears knows there is a very intelligent guy that
19 > > > want to be invisible.
20 > >
21 > > AFAIK they appear as "filtered",that's the difference between a closed
22 > > and a filtered port. The first responds with a "negative", the second
23 > > doesn't respond. Am I wrong?
24 >
25 > That's right. But no answer means there is somebody who doesn't answer.
26 > Only if the last router before the target says "Hey, there is nobody",
27 > then there is nobody (or there is an really intelligent guy, that wants
28 > to hide his host).
29 >
30 > To hide a host is always very stupid, why should you do this? There is no
31 > advantage. If you "hide" your computer an attacker knows there is an
32 > stupid guy who doesn't know anything about network security.
33 >
34 > mfg
35 > Oli
36 >
37 > --
38 > gentoo-security@g.o mailing list

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Re: [gentoo-security] firewall suggestions? Oliver Schad <o.schad@×××.de>