I am currently having to access the internet through a wireless dongle which is giving me a 2gb per month download allowance. I need to be really cautious about my internet usage.

Just this afternoon I ran out due to some process downloading 600mb of something. I have no idea what it was (although I suspect iTunes) or why it would need to download so much.

Is there anyway I can monitor which processes are using the network, or failing that set up a firewall that only allows the apps I choose to have access?


If you install Little Snitch you can monitor which application using internet. Every time any application wants to use internet you must accept or deny it, but it doesn't have an ability to measure bandwidth usage of each application.

You can see its demo here.

  • Little Snitch is awesome. – JBRWilkinson Jan 22 '11 at 14:32

600 MB doesn't sound like iTunes, unless you told it to do it.

I'd look into "Software Update...", which, in its case, can have its automated run turned off so you can run it manually.

  • Thats the first thing I thought of as well. +1 – Ryan Sharp Jan 20 '11 at 21:11
  • Looks like someone down voted you, even though you're most likely correct. – Ryan Sharp Jan 20 '11 at 22:57
  • Probably is correct. Isn't an answer to the question as asked, so it should probably be a comment where it might get voted up... – user588 Jan 21 '11 at 2:37
  • 1
    Well, I guess I could add it back as one AGAIN. It was originally a comment. At least then they can't down-vote it. – Greg Jan 21 '11 at 3:15
  • Yes, it doesn't answer my question directly, but I did look and automatic updates were switched on. So it was very useful to know! – Mongus Pong Jan 21 '11 at 9:30

HandsOff! (trial available)

is a very feature rich firewall for MacOSX. The features included which you need are:

  • prompts you when a process/applications tries to connect to the internet
  • monitoring network connections
  • settings rules for application's network connections

The total bandwith you see in the monitor is only since last boot.

enter image description here

  • This looks promising, onlt my Macbook rarely get's rebooted, and is often on WiFi, I would like to be able to reset the data at a point when I know I am about to use the dongle - do you know if this is possible? – stuffe Feb 22 '12 at 10:59
  • @stuffle The network monitor only allows to clear the connection history, or pause monitoring. – gentmatt Feb 22 '12 at 12:12

I found SurplusMeter to be very effective while using my 3G USB Stick.

SurplusMeter Screenshot

Here's also a tutorial.

  • 1
    Ooh, very good, I think a combination of this and one of the firewalls to stop software update trashing my bandwidth is likely to win the points. – stuffe Feb 22 '12 at 11:00
  • Nice tool! This helped my to limit my bandwith to 300MB/month when I lived in South Africa. :) – gentmatt Feb 22 '12 at 12:14

You might try NetUse, $8 at the App Store.

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