Configuring monitor port mode for a Switch ???

[Johnthom]

Hi all,

I have been told that we can set a switch's port into "monitor port" so that we can use this port to listen all data packets passing through the switch. But until now, I have no idea to configure my switch for this function. Please tell me what commands I have to use to configure my switch and please give me a sample configuration.

Thanks in advance for your help.

John Thom

 

[wybnormal]

2900-

interface FastEthernet0/1
port monitor FastEthernet0/2
port monitor FastEthernet0/5
port monitor VLAN1

Cat 5000 etc

switch (enable) set span 2 6/2 ; 2 is vlan # adn 6/2 is port

A very good paper from Cisco:

http://www.cisco.com/warp/public/473/41.html

Be careful.. you can sniff the vlan LOCAL to the switch.. in other words, if the traffic a switch 2 goes between it's own ports and you are on switch 1 sniffing.. you will never see the traffic even though it's all on the same vlan.

MikeS


MikeS

Find me at

http://www.packetattack.com

"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin