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Re: Zenmap Crashing and CPU Utilisation hangs at 50%
From: Ray Middleton <ray.middleton () gmail com>
Date: Tue, 18 Jan 2011 10:12:59 +0000

Hi David,

Thanks for the help, I'll let you know how I get on.


On 17 January 2011 20:31, David Fifield <david () bamsoftware com> wrote:

On Mon, Jan 17, 2011 at 02:11:11PM +0000, Ray Middleton wrote:
Hi David,

Thanks for the response.

No the problem does not happen when switching to the topology tab, I
get that far with the scans.  It is just on the main results window.

I've included the output.xml file and also an screenshot so you can see
is happening from a graphical standpoint as well as the xml.

I forgot to add in my initial email that this is on Windows 7 pro 64bit.
Once manually closing out the application after it becomes unresponsive
windows error is "NMAP front end results viewer is not responding".

I bet I know what's going on. I see that the output (the normal text
output, not the XML) is pretty long. Zenmap's live display of Nmap
output is really inefficient: it monitors the output file for any
changes, and when it changes, it re-reads the entire file from the
beginning, doing syntax highlighting and everything. When even one new
line is appended, it starts all over again. It's O(n^2) in the size of
the output.

Clearly Zenmap should only read the new lines and remember what it has
already done instead. I'll make a TODO note about this.

I don't have a good workaround to suggest other than running the command
in a terminal. (You can copy and paste the command line from Zenmap, add
a -oX option to save the output, and then open the XML file in Zenmap
later.) Another thing you might try is changing this setting to False in

enable_highlight = True

I don't know how much the highlighting contributes to the inefficiency,
but it might be enough to allow your scan to finish.

David Fifield

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