I was playing around with some ways of detecting active network connections to add as a function in one of my apps — didn’t really work out, so far — but as I was prototyping the code in AppleScript I came up with this little ditty which some of you might be able to make use of:

1. Open the Script Editor

2. Paste the code below into it and hit ‘Run’

#start of script

on getConnections()

set theCmd to "lsof +c 0 -i -n | grep -i established | cut -d \" \" -f 1 | awk '!_[$0]++'"

set theMsg to (do shell script theCmd)

display dialog "The following apps & processes are actively using your internet connection: " & return & return & theMsg with title "Net Tattler" buttons {"Refresh", "OK"} default button "OK"

set theRes to button returned of the result as string

if theRes = "Refresh" then

getConnections()

end if

end getConnections

getConnections()

#eof

If you need more information than just the names of the process, you can play around in Terminal with lsof -i. Here’s a great little tutorial.

For something a bit more heavy-duty, check out either Little Snitch or Charles Web Debugging Proxy, both of which are paid-apps but offer free trials. If even those aren’t enough to satisfy your network monitoring desires, head on over to MurusFirewall.com and check out their packet filter GUI offerings for the Mac.

Enjoy 🙂

Acknowledgements

Thanks to the folks over at Etresoft for additional suggestions.