which program is using the internet

I have the unfortunate privilege of living in a rural area without internet connection. It isn't as bad as it sounds, I usually just bring what I need home and work there, and if I have to I use dialup.

However, as slow as dialup is, I need to keep things from uselessly using up what little bandwidth I have. For example, even though I have set Firefox to not check for updates, I suspect that it is "calling home" and using up bandwidth, even when I'm just visiting some innocuous like the Google home page.

So how can I tell what program is sending traffic over the internet? The activity monitor doesn't really do that as far as I can tell (messages sent and received are always dominated by local stuff).

Any advice appreciated.

>>>bill<<<

 

Thanks, I'll take a look at it.

However, it looks more like a firewall than just a logger. Is there any utility out there that would log this kind of information?

Thanks.