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Burton Strauss wrote on 7-6-2005 18:37:
> What about ifconfig stats?  That should show the # of packets arriving at
> the interface.  If you look, the counts are consistent, but just 1/2
of what
> you expect.

With just looking at the counters of ifconfig, you also see the http
traffic to/from the Ntop webserver. When I count the packets with
'tcpdump udp port 2055' I see that the netflow packtes arrive at the
interface. But Ntop-netflow-plugin sees about 1/2.

In about 1 hour and 5 min the router sends  +/- 76,505 pkts to a
'flowtools host' which sends it to the Ntop-host. The Ntop host receives
according tho tcpdump +/- 76,513 pkts. In this period the interface
(ifconfig) receives +/- 128,012 pkts.
The Ntop-Netflow-Plugin receives +/- 28,827 pkts!


> It could be that ntop isn't pulling them fast enough from the

I think that is the problem.......

> interface, but that's just a pretty simple select() recvfrom() call pair.

Is that good/wrong? Could that be an perfomance issue?

>
> -----Burton
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf
> Of R.H.Hoek
> Sent: Monday, June 06, 2005 3:07 AM
> To: [email protected]
> Subject: Re: [Ntop-dev] netflow-plugin misses packets
>
> Burton Strauss wrote on 4-6-2005 14:25:
>
>>>How about the stats from the plugin itself?
>
>
> The packetcounts from Ntop netflow are taken from the stats from the
plugin
> itself:
>
> Flow Statistics
> Received Flows
> Flow Senders  130.89.244.12 [2,251,319 pkts]
>
> Number of Packets Received    2,251,319
> Number of Packets with Bad Version    0
> Number of Packets Processed   2,251,319
> Number of Valid Flows Received        65,850,914
> Average Number of Flows per Packet    29.2
> Number of V1 Flows Received   0
> Number of V5 Flows Received   65,850,914
> Number of V7 Flows Received   0
> Number of V9 Flows Received   0
>
> Discarded Flows
> Number of Flows with Zero Packet Count        0
> Number of Flows with Zero Byte Count  0
> Number of Flows with Bad Data         0
> Number of Flows with Unknown Template         0
> Total Number of Flows Processed       65,850,914
>
> Flowtools reports:
> -------------------
> Jun  6 09:41:00 localhost flow-capture[27759]: STAT: now=1118043660
> startup=1117802440 src_ip=127.0.0.1 dst_ip=127.0.0.1 d_ver=5
> pkts=4590376 flows=133781439 lost=0 reset=0 filter_drops=0 Jun  6 09:42:00
> localhost flow-capture[27759]: STAT: now=1118043720 startup=1117802440
> src_ip=127.0.0.1 dst_ip=127.0.0.1 d_ver=5
> pkts=4592106 flows=133831723 lost=0 reset=0 filter_drops=0 Jun  6 09:43:00
> localhost flow-capture[27759]: STAT: now=1118043780 startup=1117802440
> src_ip=127.0.0.1 dst_ip=127.0.0.1 d_ver=5
> pkts=4595919 flows=133942507 lost=0 reset=0 filter_drops=0
> --------------------
>
> Cisco Netflow reports:
> --------------------
> UTWENTE-router>sh ip flow export
> Flow export is enabled
>   Exporting flows to x.x.x.x (2055)
>   Exporting using source interface Vlan102
>   Version 5 flow records
>   *21104941* flows exported in *703498* udp datagrams
>   0 flows failed due to lack of export packet
>   0 export packets were sent up to process level
>   0 export packets were dropped due to no fib
>   0 export packets were dropped due to adjacency issues
>   0 export packets were dropped due to fragmentation failures
>   0 export packets were dropped due to encapsulation fixup failures
>   0 export packets were dropped enqueuing for the RP
>   0 export packets were dropped due to IPC rate limiting
> UTWENTE-router>sh mls nde
>  Netflow Data Export enabled
>  Exporting flows to x.x.x.x (2055)
>  Exporting flows from y.y.y.y (49744)
>  Version: 5
>  Include Filter not configured
>  Exclude Filter not configured
>  Total Netflow Data Export Packets are:
>     *3892409* packets, 0 no packets, *112837207* records  Total
Netflow Data
> Export Send Errors:
>         IPWRITE_NO_FIB = 0
>         IPWRITE_ADJ_FAILED = 0
>         IPWRITE_PROCESS = 0
>         IPWRITE_ENQUEUE_FAILED = 0
>         IPWRITE_IPC_FAILED = 0
>         IPWRITE_MTU_FAILED = 0
>         IPWRITE_ENCAPFIX_FAILED = 0
> UTWENTE-router>sho clo
> 09:42:52.569 MET-DST Mon Jun 6 2005
> --------------------
>
> This measurement runs from Fri 3jun
> Cisco and Flowtools reports both the same packets/flows:
>
> Cisco: 21104941+112837207= 133,942,148  flowtools: 133,942,507 (flows)
> Cisco: 703498+3892409= 4,595,907        flowtools: 4,595,919   (packets)
>
> Netflowplugin: 65,850,914 flows
> Netflowplugin: 2,251,319 packets
>
>
> N.B. counters are reset and read manualy on 'about' the same time.
> (within 30 sec)
>
>
>>>-----Burton
>>>
>>>-----Original Message-----
>>>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
>>>Behalf Of R.H.Hoek
>>>Sent: Friday, June 03, 2005 9:15 AM
>>>To: [email protected]
>>>Subject: [Ntop-dev] netflow-plugin misses packets
>>>
>>>Dear Ntoppers,
>>>
>>>Some weeks ago I already mentioned that I experience some problems
>>>with Ntop in combination with Netflow from a Cisco6509 with supervisor2.
>>>Some of you gave me some hints, but nothing couldn't solve my problem
>>>(see below).
>>>
>>>The problem is that the Netflow-plugin misses about 40-60% of the
>>>netflowpackets send by the Cisco6509. Some figures:
>>>
>>>Last night, in a period of about 17 hours the Cisco has sendout
>>>31,274,087 flows in 1,073,210 packets.
>>>The Netflow-plugin reports it received 16,035,229 valid flows in
>>>548,345 packets. The plugin reports no discarded flow.
>>>
>>>My first though is that it is not the hardware. I (can) run Ntop on
>>>two different systems, but experience on both the same problem:
>>>System1:
>>>Dual-Xeon 3.2GHz, 5GB RAM, with 4 disks in two hardware SCSI raidsets
>>>(RAID1)(18GB,73GB) and 100M/1G Ethernet interface with a 100Mbps
>>>networkconecction. On this system the OS is SuSE-UnitedLinux 8. (2.4
>>>kernel) System2(originally meant for probe):
>>>Dual-Xeon 3.2GHz, 3GB RAM, with 2 disks in a hardware SCSI raidsets
>>>(RAID1)(18GB) and 100M/1G Ethernet interface with a 100Mbps
>>>networkconecction. On this system the OS is Debian Sarge 2.6 kernel.
>>>
>>>I have done testing with Ntop 3.1 and the latest CVS versions -> same
>>>results. With tcpdump I did some counting. The conclusion is that the
>>>packets send by Cisco6509 are received on the system Ntop is running
>>>on, but are discarded/missed by the Netflow-plugin
>>>
>>>Answers on some questions:
>>>1)
>>>Ntop is running with --interface-none, --track-local-host and the
>>>Netflow pseudo-nic is selected.
>>>2)
>>>Even, with RRD-plugin is set to low-detail, and data to dump is 'none'
>>>does not solve the problem
>>>3)
>>>for testing I have incremented MAX_SUBNET_HOSTS to 8192/16384 in
>>>globals-defines.h.
>>>Load avg 0.14 (98% idle)
>>>The memory usage is about 1.8GB (3.3 GB free) after 1 hour Ntop is
>
> started.
>
>>>4)
>>>The load graph and (traffic)protocol-distribution should display the
>>>total network load of the Cisco6509 when the pseudo-nic is selected. I
>>>have seen this on a Ntop system with low netflowtraffic.
>>>5)
>>>In a test config the Cisco-Netflow is first send to system2 and
>>>redistributed with flow-fanout to system1 running Ntop. On system2 I
>>>do flow-capture and flow-stat. When I compare this output with
>>>Ntop-output, the differences are very large as of 5min net workload
>>>and protocol distribution.
>>>6)
>>>The average netflowstream is about 20 packets/s. But I have seen
>>>bursts of 900 packets/s
>>>
>>>
>>>
>>>I think that the last point is possibly the problem. With these bursts
>>>the netflowplugin inputbuffer is overloaded ?
>>>Is there a way to tune this buffer? Or does anybody else has some hints?
>>>
>>>
>>>--
>>>
>>>Groeten,
>>>
>>>Roel H.Hoek, SeniorNetworkmanager
>>>Dienst Informatietechnologie, Bibliotheek en Educatie (ITBE)
>>>Universiteit Twente,  Postbus 217,  7500 AE  Enschede kmr SP 422,
>>>telefoon: 053 - 489 4598,  fax: 053 - 489 2383
>>>e-mail: [EMAIL PROTECTED] http://www.utwente.nl/itbe
>>>
>
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>
> --
>
> Groeten,
>
> Roel H.Hoek, SeniorNetworkmanager
> Dienst Informatietechnologie, Bibliotheek en Educatie (ITBE) Universiteit
> Twente,  Postbus 217,  7500 AE  Enschede kmr SP 422, telefoon: 053 - 489
> 4598,  fax: 053 - 489 2383
> e-mail: [EMAIL PROTECTED] http://www.utwente.nl/itbe
>
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- --

Groeten,

Roel H.Hoek
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