Nmap Development mailing list archives
Speeding up single ports scans over large networks
From: "testic" <testic () testic demon co uk>
Date: Fri, 19 Sep 2003 00:35:51 +0100
I have recently been wanting to scan largest networks to discover if a single port is open. I have found that this seems to be exceedingly slow, I expected that seeing as I was using a connect() scan I could scan, say, 256 hosts at a time with, for example, a 2 second timeout per host. This way the rate at which the hosts would be scanned would be rather high, a minimum of 128 per second in fact. Instead what I am finding is that each host takes several seconds to scan a single port. I have experimented with all the flags, turned of DNS lookup, turned all the timeout options to very low values, increased the number of sockets etc, but still its taking a silly amount of time to scan a single host. OS detection is off, I am using the +V patch, but not using the -sv flag in order to save time. Is there a better of doing this? Perhaps a script of some sort to execute 256 nmap instances? I am scanning a /16 network so speed is of the essence :) Perhaps if there was a way to disable common-service lookups for open/filtered/closed ports? Or a flag to specify how many hosts to scan in parallel? Maybe there is, but I couldnt find it. Any input greatly appreciated :) testic --------------------------------------------------------------------- For help using this (nmap-dev) mailing list, send a blank email to nmap-dev-help () insecure org . List run by ezmlm-idx (www.ezmlm.org).
Current thread:
- Speeding up single ports scans over large networks testic (Sep 18)
- Re: Speeding up single ports scans over large networks Fyodor (Sep 18)
- Re: Speeding up single ports scans over large networks Fyodor (Sep 18)
- <Possible follow-ups>
- Re: Speeding up single ports scans over large networks testic (Sep 18)
- Re[2]: Speeding up single ports scans over large networks Bo Cato (Sep 18)
- Re: Speeding up single ports scans over large networks testic (Sep 18)
- Re: Speeding up single ports scans over large networks Fyodor (Sep 18)