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RE: Network Configuration Question
From: "Madalina Sersea" <Madalina.Sersea () connex ro>
Date: Thu, 7 Nov 2002 16:23:17 +0200

WLBS (Windows Load Balancing Service) or some types of clusters may be the cause. The hosts that participate in such a 
"WLBS construct" have each their own IPs and own MACs. But they comunicate with a virtual IP and virtual MAC. The first 
switch (the hosts are directly connected in) can't learn this virtual MAC and can't attach this MAC to a specific port. 
That's why the switch will forward the packets to these hosts on every port. Not only you, but every other computer 
with the network card in promiscuous mode will see theses packets , even in the other switches in the ierarchy.  
Look in the switch, into the table that keeps the correspondence MAC-port.

Madalina SERSEA
LAN/WAN Development Engineer

    We are on a 100mbs switched network (I believe switched but ..).

    Now imagine my surprise when I could pick up traffic 
from around 6
machines, including HTTP, POP, SMTP and all the associated passwords.

    Some of the machines were geographically close to me in 
the office 
but not all. How could this happen on a switched network - 
has one of 
the switches fallen over into broadcast mode or something? 
If so how do 
I go about determining (remotely) why/how it has fallen 
over, who else 
is on the segment, and what other avenues do I have to explore?

    Thanks in advance

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