[EMAIL PROTECTED] schrieb:

hi Sebastian,

any special requirements on Cflow or gnuplot version? for png output I get
only:

$ ./flow-histogram -network x.x.x.0/24 \
-read ft-v05.2006-02-15.221539+0100 -write histogram.png
Illegal division by zero at ./flow-histogram line 729.

csv output works apparently correctly, though.

cheers,
Kresimir


On Wed, Feb 15, 2006 at 11:08:34PM +0100, Sebastian Krieger wrote:
Hi,

here is my reverge for all the great support I got from the list in the past ;-) Maybe it is usefull for someone.

I wrote a little perl script to create histograms for netflow data. Either you can plot the data to a png or you write it in csv format. It is possible to define several networks as local for a graph. E.g. for representing the traffic of a whole country even if the subnets are completely different. The graphs look similar to the output from Flowscan module JKFlow, because I was really impressed by it. But you do not need to pre-define sites and services etc. and you also do not need to store tons of data in rrd files or a database after scanning incoming netflow logs in realtime. If you notice you need a special histogram at any time you only filter the logs you want and process it by this script. Also you can set the interval between checkpoints to adjust the sampling for your graph at execution time. Unfortunately it is not possible to read flow data from stdin, because it is needed to read the data twice to prevent the script from being a memory eater. At first it makes service detection and collects top statistics. After that it evaluates the flow data based on this.

The script is still dirty code but for me it works fine. Please get in contact with me for update issues if someone will use this script.

I temporary placed the script on...
http://www.freewebs.com/skrieger/

There you can also find a sample graph with the inbound/outbound traffic on a 2 Mbit line with several subnets behind by remoteips-services. I placed black boxes on the areas where local networks and the remoteips are shown to protect privacy.

Bye
Sebastian


<<< Perl Modules: >>>

The following perl modules are used:

use Cflow;
use Net::Patricia;
use Getopt::Long;
use POSIX qw(ceil);
use Date::Manip;


<<< Gnuplot Version: >>>

In my environment it works great to generate the graphs in png format with gnuplot version 4.0 patchlevel 0. In lower versions of gnuplot the syntax is different and this may result in an error. It's not needed to use a higher version of gnuplot then 4.0 p0 with the known stacking options, because the stacking/cumulation is calculated within the perl script.


<<< Filtering Netflow Data: >>>

You should better pre-filter your netflow logs with e.g. flow-nfilter because its faster than matching only by Net::Patricia perl module.


<<< Usage for flow-histogram: >>>

Usage: flow-histogram -network <IP/MASK[,IP/MASK]> -read <FILE> -write <FILE> [ -options ]

-network <IP/MASK> = Local network(s) with in/out (e.g. 192.168.1.0/24[,10.1.1.0/24])
-read     <FILE>    = Input file with flows (binary flow-tools format)
-write    <FILE>    = Output file for graph
-interval <SECONDS> = Stat interval for graph in seconds (default: 300)
-top      <COUNT>   = Show only top rows in graph with others (default: 10)
-unit     <UNIT>    = Calc values into special unit (default: Kbits/s)
-show <FIELD> = [protocols|services|remoteips|localips] (default: services)
                    or combination [remoteips-services|localips-services]
-output   <TYPE>    = Type of output [plot|csv] (default: plot)
-version            = This help
-help               = This help

flow-histogram 1.5, 12.02.2006 by skr



Hi Kresimir,

I was able to reproduce the problem. It was a failure in the script.

During average calculation for the summary in the graph it was fatal if a type of connection had only traffic in one direction. The problem is solved now.

The updated version is now available...
http://www.freewebs.com/skrieger/

Please give me feedback.

Regards
Sebastian

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