Home page logo
/

nmap-dev logo Nmap Development mailing list archives

Re: Nmap probes per port
From: Paul Johnston <paul () westpoint ltd uk>
Date: Fri, 19 Mar 2004 10:29:20 +0000

Hi,

I guess you're using a connect() scan? The large number of retries occurs because the kernel retries sending the SYN several times for each connect, while nmap also retries calling connect. Using SYN scan will reduce the number of retries to 6, which I believe is around the right number. However I've found the timing of SYN and connect scan to be almost identical. You may want to consider using a fixed rate port scanner, such as scanrand.

Paul

Nmap-3.50 sends approx 16 TCP SYNs for a filtered port.
My aim is to reduce the time taken to do a full port scan
and by sending less probes per port be slightly more
stealthy. Ideally I'd like one probe per port sent, I know
this may affect the reliability of the results.

--
Paul Johnston
Internet Security Specialist
Westpoint Limited
Albion Wharf, 19 Albion Street,
Manchester, M1 5LN
England
Tel: +44 (0)161 237 1028
Fax: +44 (0)161 237 1031
email: paul () westpoint ltd uk
web: www.westpoint.ltd.uk



---------------------------------------------------------------------
For help using this (nmap-dev) mailing list, send a blank email to nmap-dev-help () insecure org . List archive: http://seclists.org



  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]