I'm pretty sure I've already replied, but it showed up new...

Update to 2.0.99 and use the -j | --border-sniffer-mode  (it's not available
in 2.0), what this does is to eliminate ntop's usage of MAC addresses, which
are being changed by the switch as part of the mirroring process (it has to
do this to send out valid TCP/IP packets).

-----Burton

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Sancho Lerena
Sent: Tuesday, May 14, 2002 3:16 AM
To: [EMAIL PROTECTED]
Subject: [Ntop] Problems with IP / MAC in a VRRP enviroment.


Hello,

I'm using NTOP in a production enviroment to check network traffic and
efficiency of our network. We have detected a problem with NTOP: it assign
MAC to IP with nosense. We have about 100 hosts in out NOC, and NTOP tell us
that three "hosts" are taking all the load...

If you look at the MAC you find a VRRP MAC assigned to an IP of SMTP server.
I think that something was wrong. I suppose that Cabletron Load Balancing
and/or VRRP setup of our firewalls and Cabletron Switches can be confusing
NTOP.

We have a FastEthernet portmirror on a Cabletron 8000 and 8600 (we have two
NTOP's and we have similar problems).

Examples:

Info about host 10.y.x.41 (taking about 90% of our NOC traffic, impossible
in real life).
IP Address 10.y.x.41  [unicast]
First/Last Seen 05/06/02 19:52:10  -  05/14/02 10:48:03 [7 day(s) 14:55:53]
Last MAC Address/Router  00:00:5E:00:01:04

In other 2.0 version it has a "Duplicated IP or Wrong netmask" warning, but
I'm using ntop v.2.0.0 MT [i686-pc-linux-gnu] (03/11/02 03:38:09 PM build)
and this error dont appear. This host is a Debian Woody with kernel 2.4.6
and 3Com PCI 3c905B Cyclone  NIC's.

I'm using other NTOP, version ntop v.2.0.0 MT [i686-pc-linux-gnu] (04/12/02
11:48:31 AM build), with debian Woody using 2.2.19 kernel, and the same
nic's.

Setup is a basic debian config with some changes in /etc/init.d/ntop script

USER="ntop"
GETOPT=" -E -n -c -m z.x.y.0/16,z.x.y.0/16"
PORT="xxxx"
INTERFACES="eth1"
SAVE="2"
TRACE="2"

start-stop-daemon --start --quiet --name $NAME --exec $DAEMON -- \
  -d -L -u $USER -w $PORT -p /etc/ntop/protocol.list -P $HOMEDIR \
  -S $SAVE -a /var/lib/ntop -R /etc/ntop/rules -i $INTERFACES \
  -t $TRACE -O $LOGDIR $GETOPT

Thanks for your help,

Un saludo,

        Sancho Lerena

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