Security Basics: Re: how to find out a list of available ftp servers on LAN

[Turbo <sandeep_kr () students iiit net>]

I wonder why are the results not the same for both of us. On my 
network :-
$ time nmap -n -P0 -sT -p 21 -oG out  --max-retries 0 -iL IPs.txt
...
...
Nmap finished: 8960 IP addresses (8960 hosts up) scanned in 264.766 
seconds
real    4m24.861s
user    4m8.116s
sys     0m2.164s

$ time ./NetworkScanner 21 255 IPs.txt
...
...
real    1m42.182s
user    0m0.264s
sys     0m2.284s

The reason seems to be the no. of addresses to scan. Here I am trying to 
scan 8960 addresses. For 256 addresses here are the results( which is 
similar to yours):-
$ time nmap -n -P0 -sT -p 21 -oG out  --max-retries 0 -iL IPs.txt
...
...
Nmap finished: 256 IP addresses (256 hosts up) scanned in 0.976 seconds

real    0m0.984s
user    0m0.112s
sys     0m0.036s

$ time ./a.out 21 255 IPs.txt
...
...
real    0m3.155s
user    0m0.008s
sys     0m0.136s

I did all my fine-tuning using 8960 IPs, and I found nmap was slower. But 
this example makes me believe that I can still fine-tune nmap better. I 
will try and update you.
Thanks.

On Sat, 5 May 2007, Pranay Kanwar wrote:

> Hi,
>
> Looking at your problem nmap can do it faster :)
> ( kindly ignore the ip class :) )
>
> %time ./propecia 172.31.1 21
> 172.31.1.11
> 172.31.1.15
> 172.31.1.24
> 172.31.1.41
> 172.31.1.60
>
> real    0m1.029s
> user    0m0.000s
> sys     0m0.008s
>
> %time nmap -n -P0 -sT -p 21 -oG out  --max-retries 0 172.31.1.0/24
> &>/dev/null ; grep open out
>
> real    0m0.916s
> user    0m0.036s
> sys     0m0.037s
> Host: 172.31.1.11 ()    Ports: 21/open/tcp//ftp///
> Host: 172.31.1.15 ()    Ports: 21/open/tcp//ftp///
> Host: 172.31.1.24 ()    Ports: 21/open/tcp//ftp///
> Host: 172.31.1.41 ()    Ports: 21/open/tcp//ftp///
> Host: 172.31.1.60 ()    Ports: 21/open/tcp//ftp///
>
> The option -P0 don not ping host before scanning, -n no reverse dns
> resolution, max retries 0 , all these options make nmap sort of
> *similiar* to propecia.
>
> Note: nothing beats nmap :D.
>
> Regards,
>
> warl0ck // MSG
> http://www.metaeye.org
--
I do know everything, just not all at once. It's a virtual memory problem.
Home Page : http://students.iiit.ac.in/~sandeep_kr
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