Where in a network and how do you connect Ethereal? 1

[rackit]

Ethereal is a free network protocol analyzer for Unix and Windows. I'm in the process of learning how to use a protocol analyzer and need help.
Where in a network (physically) do you place Ethereal.
How do you place it, since is runs on a pc. Do you use the pc like a tool and place it between a host and a switch or router?
Any information you can share will be helpful!

 

[fmonteiro]

In a switched environemnt you will need to mirror the port when the device you want to monitor is connected to the port where your protocol analyzer is installed. Suppose you want to monitor a host connected to, lets say, port 1 of your switch. Suppose you have installed you protocol analyzer on port 20. You must tell your switch to mirror the traffic on port 1 to port 20 (for Cisco switches this command is "set span&quot. Some switches allows you to mirror an entire VLAN. You may circumvent the need for a mirror using a hub to insert you protocol analyzer.