Ethereal-users: [Ethereal-users] Broadcasts which shouldn't be broadcasts

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From: "Carsten Holfelder" <carsten.holfelder@xxxxxxxxxxxxxxxx>
Date: Thu, 9 Dec 2004 07:26:45 +0200
Good Day,
 
I have noticed over time the network seems to slow down. So I have installed ethereal on my computer and noticed the following.
 
I have got a switched network with about 1600 devices connected to it.I noticed that I am able to sniff a lot of packets that should have been switched - Directed Traffic. When I check the data packets I noticed that there is a destination MAC Address in the data packet. I connected the packet sniffer to a different section on the network and it is the same. When I check on the switches the MAC Address is not in the ARP table. I have increased the aging time of the arps cache and it has made no difference. My main switches are Dell Poweredge 5324 and the rest are a mix between 3Com and Cabletron. The switches are not even sending a broadcast packet asking for the MAC Address of the Server or Computer. When I check the port where the server is connected to it doesn't show the MAC Address of the server.
 
The main problem is with a web based application that run a SQL server in the background. There are four IIS servers running with microsoft NLB (Network Load Balancing) between them. Two servers are connected in one switch and the other two in a anouther switch. The replys from the server to the clients are directed. It is only the traffic that is going to the servers that are being broadcast. The servers have got two nics in them. One is for the NLB which the clients access and the other is used for a maintenance connection.
 
I know that this is not about ethereal but a network problem, but I am hoping that there is someone who knows what the problem is and will be able to assist me to solve it.
 
Thanks
Carsten Holfelder

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