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Packet analyzer question

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lrock

IS-IT--Management
Jan 29, 2008
9
I have a question that I just cant quite get my head around. I need to put a Packet sniffer on the network. But I cant seem to get it in a place that is getting data from all computers. My setup is like this

Router --> Firewall --> Switch --> Desktops
--> Switch --> Desktops

If I plug into the switch I get broadcast data from all computers but unicast data goes by without being detected. I know that is the point of the switch is to keep unwanted unicast packets out of the picture. But here is the question. Do I have to put a hub between the firewall and switch and hang a workstation off the hub as well to capture all the data coming out of the switch?

Just thought I would bounce that off of you?

 
To catch unicast packets you would need the two switches the desktops connect to be able to mirror all the ports to one port to sniff in. I am not sure off the top of my head if switches do that. I think you can though.

If you put a hub between the desktop switch and the firewall you will never see packets that do not leave the switch.

If you are only concerned with data that goes from the desktops off your network you can mirror (span port in cisco terms) the uplink port on each switch and sniff.



Gb0mb

........99.9% User Error........
Ubuntu -- African for I can't install Gentoo
 
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