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Packet Capturing

Hi all I want to do some 'sniffing' on my network due to users reporting speed issues on the LAN, I have PRTG installed but I am not seeing anything unusual in the graphs to indicate high utilisation on the LAN I have downloaded and installed Ethereal. On my system of course in a switched network, I am seeing traffic over the wire, but it is only traffic originating or destined for my IP and of course broadcast traffic I remember there was a way on a Cisco switch to set a port that basically acts as a conduit for all traffic that passes over the fabric I want to set a system up to capture all data packets over the network for analysis, if someone could tell me the best way to do this it would be appreciated

Scott

Reply to
Scooty
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Hi Scott,

You are looking for "Port Monitor mode". Its called different things on different platforms but essentually that's what it is. Look under your device specific documenation.

Cheers.....................pk.

Reply to
Peter

The following is an example of Switch Port Analyzer (SPAN) on a Cisco 2950T:

e.g.:

monitor session 1 source interface Fa0/1 monitor session 1 destination interface Fa0/16 encapsulation dot1q

In this case I chose an inter-VLAN routing trunk port (Fa0/1) as the SPAN source, and the Fa0/16 port as the SPAN destination. I used "encapsulation dot1q" to preserve the 802.1Q headers, but that's optional.

As the other responder stated, you should consult the documentation for your specific platform.

Best Regards, News Reader

Reply to
News Reader

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