Hi,

The 5.2.9 seem to be ok but in have another issue as explained with it.
The netflows generated dont contain the real bytes exchanged.
Always 46 bytes.

PS:
I agree about the fragmentation but a lot of applications protocols
use the IP fragmentation schem when using UDP.
SIP, UDP VPN,  are parts  one of them.






Luca Deri
Fri, 12 Feb 2010 14:13:34 -0800

Hi
please download nProbe 5.5 that contains some improvements for flow handling. I
have not done much changes in the fragment code but 400k fragments/sec is an
indicator that the problem is not on nProbe but on the networks. So I would
start investigating here first as having so many fragments is a source of
problems

Luca

On Feb 12, 2010, at 9:55 PM, Canope wrote:

> Hi,
>
> I've made some tests with nprobe 4.9.4 and nprobe 5.2.9 and i've
> encountered two issues :o(.
>
> The first one is with the 4.9.4 version:
>
> When a great amount of udp fragmented (more than 400000/s)  packets is
> analysed, nprobe start to loose packets.
> I've checked the code and  the problem seem to be located on the
> fragmented subroutine.
> If i reduce the delay for the "lastSeen" from 30 seconds ( hardcoded)
> to less, the issue disapear but the probe produce more flows per
> seconds.
>
> The second one with the 4.9.4 version:
>
> I have to change imcrement the MAX_EXPORT_QUEUE_LEN to a bigger value
> (524280) of handling the workflow :o(
>
> The first one is with the 5.2.9 version:
>
> - the netflow v9 generated packets dont contain the "right" size of
> the messages on the "in_bytes" section.
> - The flow generated with the 4.9.4 are "ok" but i'm looking for
> something possibily better since i've seem some interresting change on
> the fragment handling method.
>
> The second one with the 5.2.9 version:
> I have to change imcrement the MAX_EXPORT_QUEUE_LEN to a bigger value
> (524280) of handling the workflow :o(
>
>
> I'm available if someone whant more informations.
>
>
>
>
> Thanks in advance,
> _______________________________________________
> Ntop-misc mailing list
> [email protected]
> http://listgateway.unipi.it/mailman/listinfo/ntop-misc

---

"Debugging is twice as hard as writing the code in the first place. Therefore,
if you write the code as cleverly as possible, you are, by definition, not
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