Monitor network traffic on a per-app basis in OS X?

Question

Title says it all. I'm looking for an app for OS X that will tell me what applications are using the network and what their in/out is. I can get most of the way there with LittleSnitch but it's the bandwidth part that it fails at.

The only app I've come across that comes close is "Rubbernet" and while it does look like it would probably do what I want, it's very expensive (more than LittleSnitch) and doesn't look like it gets regular feature updates.

Any recommendations?

Answer 1

There is a free command line program called iftop that may be helpful. You can install it via Homebrew.

    brew install iftop

Once installed:

    sudo iftop -P -i en1

-i and the interface you wish to monitor.

Answer 2

This question might be a duplicate of this one. As explained in the comments below @mikl's answer, Little Snitch provides a graphical interface showing per-app trafic. This functionality is available on the menu bar icon, "Show Network Monitor". It is still available when running in demo mode (free mode).

Also, a dmg is provided for the installation.