sloow wrote:
I guess all I really want to do is see how much and what is going in and out of the computer. If there was a way to see when passwords, credit card #'s, etc were being transferred that would be helpful.
If you want to see the information going out over one of your network interfaces, you can use <code>tcpdump</code>, which ships with Mac OS X (you can get more information by typing <code>man tcpdump</code> from the Terminal). Since it shows you everything, the amount of information it presents is, well, overwhelming.
As for being able to detect when credit card numbers, passwords, etc, are being transmitted, well, that's a hard problem. Tools like <code>tcpdump</code> only show you what's being sent over your network, and make no attempt to interpret the data[1]. Also, if the data is encrypted (e.g., you're accessing a secure webserver), the encrypted data won't make any sense at all.
I hope this makes sense. If it doesn't, let me know and I'll see if I can clarify it.
[1] You might be able to interpret the data on a connection-by-connection basis, but there's no general way to determine if a stream of data contains, say, a password.
