John H. Robinson, IV wrote:
James G. Sack (jim) wrote:
John H. Robinson, IV wrote:
This seems to duplicate some of nmap's functionality. Do you often run
across systems that have netcat installed, but not nmap?
I did indeed used to. These days, always got both I guess.
Perhaps I never got comfortable with nmap options, whereas I figured out
how to use nc to ask this simple question, in days past -- so I still
hang on to it.
#Does host H have a (tcp) port P open?
portlook.sh H P
Is that trivial with nmap?
No. You have to add a -p flag.
% nmap google.com -p 80
Starting Nmap 4.03 ( http://www.insecure.org/nmap/ ) at 2006-09-12 20:47 PDT
Interesting ports on 64.233.187.99:
PORT STATE SERVICE
80/tcp open http
Nmap finished: 1 IP address (1 host up) scanned in 5.231 seconds
But nmap is a complete scanner:
% nmap google.com yahoo.com -p 80
% nmap google.com yahoo.com -p 80,443
it will even do netgroups. The large delay above (5.231 seconds) was the
reverse DNS. You can stop that with -n.
I tend to use netcat to open up network pipes, and nmap for service/port
scanning, even if it is just one port on one host I am interested in.
Ah, OK, I guess even I might be able to remember that syntax.
FWIW: the portlook script originated in a very simple requirement to
test a port being open and return a result code to another program.
Regards,
..jim
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