I'd like to know exactly what is leaving my laptop and going on the wire.

I used to use Little Snitch for this, but apparently it's possible to do the same thing with ipfw.

How would I go about doing this?

Running OS X 10.6.4.

  • 2
    For reference. I suggest you edit your question title to something likie "use ipfw to show what processes are making connections".
    – Andrew
    Jul 24, 2010 at 15:46
  • I think Andrew is right. ipfw exists on more than just Mac OS, but Little Snitch is exclusive to Mac OS. You might get better (or faster) answers that way.
    – zneak
    Jul 24, 2010 at 17:59
  • Ipfw is totally the tool to use.
    – chiggsy
    Dec 4, 2010 at 21:28
  • @Andrew,zneak I agree, but little snitch is alone as far as functionality offered.
    – chiggsy
    Dec 4, 2010 at 21:30

1 Answer 1


you can use the tcpdump command to see your network traffic


open Terminal.app and type

sudo tcpdump -i en1

en1 should be your wireless port, and en0 is usually your ethernet port

type ifconfig for a list

To use ipfw, I believe you add a logging clause to your rules. When a packet matches a rule, it will be logged. Its been years since I've use ipfw, so you best check the manual:

or type man ipfw into Terminal.app

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