[ale] nmap and masked ports

[Joe Steele]

"The default  is  to  scan  all ports  between  1  
and  1024  as  well as any ports listed in the 
services file which comes with  nmap."

(man nmap)

--Joe

-----Original Message-----
From:	John Wells [SMTP:jbwellsiv at yahoo.com]
Sent:	Thursday, January 17, 2002 11:29 AM
To:	ale at ale.org
Subject:	[ale] nmap and masked ports

I've been working in Canada for the past couple of
weeks at one of our satellite locations and late the
other night found myself in need of our local DNS
server's IP.  Easiest way I could figure out how to do
it was to use nmap to scan our network for port 53. 
Anyway, after finding it, I decided to have a look at
some of our test boxes and see what they had open. 
Although I knew both boxes ran Netscape Enterpise web
servers on ports 4020 and 4021, when I nmapped them
these ports did not show up.

However, if I did an "nmap -p 4021 testbox" it would
show it as an unknown port in state "open".

My question is, is Netscape somehow masking these
ports to hide from typical scans?  I've played around
with the different nmap flag combos but can't get the
ports to show up unless I specify them explicitly with
the -p option.

Thanks for your time.

JOhn


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