RE: Asynchronous DNS Patch

["Sina Bahram" <sbahram () nc rr com>]

Hi Doug,

I ran the windows binary on xp sp2.

I notice some speed increases, but only after a sort of startup time.

For example, I did a list scan of 256 hosts, and it took it two seconds to
kind of wer up before dumping them all to the screen. I could tell it was
doing it in the background since when they did get dumped to the screen, it
appeared to be all simply IO, not writing it as it goes ...

The interesting part is that I did the same scan again ... Holy cow that was
fast!

So, is that because of caching in the DNS server, or something on your end?
I noticed the same behavior for 32k hosts.

Now, as for the startup time ... I think I might have some ideas on that. I
am guessing since your are doing this in a multithreaded way, you are having
to sort your results ... I want to look at the code, and see if we can
implement something like bucket sort to sort in n time, rather than n*log(n)
...

Take care,
Sina

-----Original Message-----
From: nmap-dev-bounces () insecure org [mailto:nmap-dev-bounces () insecure org]
On Behalf Of doug () hcsw org
Sent: Tuesday, December 06, 2005 12:40 AM
To: nmap-dev () insecure org
Subject: Asynchronous DNS Patch

Hello nmap-dev,

Just letting anyone interested know that I'm working on an asychronous
reverse DNS patch to improve nmap's performance in large scans. I've gotten
some good results so far: sometimes as fast as a 30 fold improvement in the
DNS portion.

You can download the patch against nmap-3.94ALPHA1 here:

http://www.hcsw.org/nmap/

There's unfortunatley some windows bugs. I would be very appreciative if
somebody would test my windows binary I have available on my site.

Testing on unix platforms would also be appreciative. Keep in mind the patch
is still in heavy development and I would love to hear your comments!

Doug Hoyte



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