[Ti] Privacy

[Mark C. Langston]

On Sun, Jun 15, 2003 at 05:43:21PM +0200, Trevor J. Hutley wrote:
> At 09:03 +0100 15-6-2003, Tarik Bilgin wrote:
> >if you want a layman's review of your internet profile... try using 
> >https://grc.com/x/ne.dll?bh0bkyd2 and click the "test my shields" 
> >and "probe my ports" buttons to get an idea of what ports and 
> >services your computer is offering.
> 
> 
> Tarik - a very interesting URL !
> 
> I ran all the test options, and only got a completely positive and 
> encouraging report (appended).



A slight caveat emptor:  grc.com is run by someone who's regarded as
a crackpot in professional computer security fields, and that web-based
portscanner of his is neither accurate nor thorough.  Don't be lulled
into a false sence of security by the output.

If you truly want a thorough analysis of your ports, download and
compile nmap (http://www.insecure.org/nmap/), and run it against your
IP address, with the following switches:

nmap -P0 -sS -O a.b.c.d
nmap -P0 -sU -O a.b.c.d


...where a.b.c.d is the IP of the system you want scanned.  It'll
take a while, but it'll give you a much more thorough and accurate
accounting of your TCP and UDP footprint.  It'll also use passive
techniques to "fingerprint" your traffic and determine what OS you're
running.  If the fingerprinting is successful, you might want to look
into tweaking things such as the TCP sequence generation method, and
the default TTL values.

-- 
Mark C. Langston                                    Sr. Unix SysAdmin
mark at bitshift.org                                       mark at seti.org
Systems & Network Admin                                SETI Institute
http://bitshift.org                               http://www.seti.org