How To Enable Wireless Monitoring Macbook Pro
Use Terminal
You can use the airport utility.
It's located in a very obscure place, so I suggest creating a symbolic link to it:
ln -s /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport /usr/local/bin/airport

Now, you can put the WiFi (Airport) adapter into monitor mode:
sudo airport en1 sniff 6

This will sniff all packets on adapter en1 channel 6.  It will save a .cap file in /tmp/airportsniffXXXXXXXXX
You can view the output through Wireshark or issue the command tcpdump -r [filename].  For example, the following is the capture of my wireless adapter in monitor mode for a few seconds...
 18.0 24.0 36.0 54.0 Mbit] CH: 1, PRIVACY
17:37:37.746644 35635598us tsft 1.0 Mb/s 2412 MHz 11g -82dB signal -82dB noise antenna 0 Probe Response (yoyo) [1.0* 2.0* 5.5* 11.0* 18.0 24.0 36.0 54.0 Mbit] CH: 1, PRIVACY
17:37:37.774068 35662623us tsft bad-fcs 1.0 Mb/s 2412 MHz 11g -82dB signal -82dB noise antenna 0 Probe Response (LORRAINE) [1.0* 2.0* 5.5* 11.0* 18.0 24.0* 36.0 54.0 Mbit] CH: 1, PRIVACY
17:37:37.782831 35671401us tsft bad-fcs 1.0 Mb/s 2412 MHz 11g -84dB signal -82dB noise antenna 0 Probe Response (LORRAINE) [1.0* 2.0* 5.5* 11.0* 18.0 24.0* 36.0 54.0 Mbit] CH: 1, PRIVACY
17:37:37.793357 35683064us tsft 1.0 Mb/s 2412 MHz 11g -63dB signal -82dB noise antenna 0 Beacon (Go Noles ) [1.0* 2.0* 5.5* 11.0* 18.0 24.0 36.0 54.0 Mbit] ESS CH: 1, PRIVACY
17:37:37.796149 35686928us tsft wep 1.0 Mb/s 2412 MHz 11g -62dB signal -82dB noise antenna 0 Data IV:4767c7 Pad 20 KeyID 1
17:37:37.816820 35706464us tsft 1.0 Mb/s 2412 MHz 11g -79dB signal -82dB noise antenna 0 Beacon (yoyo) [1.0* 2.0* 5.5* 11.0* 18.0 24.0 36.0 54.0 Mbit] ESS CH: 1, PRIVACY
17:37:37.898203 35787820us tsft 1.0 Mb/s 2412 MHz 11g -62dB signal -82dB noise antenna 0 Beacon (Go Noles ) [1.0* 2.0* 5.5* 11.0* 18.0 24.0 36.0 54.0 Mbit] ESS CH: 1, PRIVACY
17:37:37.919172 35808864us tsft 1.0 Mb/s 2412 MHz 11g -81dB signal -82dB noise antenna 0 Beacon (yoyo) [1.0* 2.0* 5.5* 11.0* 18.0 24.0 36.0 54.0 Mbit] ESS CH: 1, PRIVACY


Use a GUI

Launch Wireless Diagnostics.  Press CommandSpace and start typing &quot;Wireless Diag...&quot;.  Press Return when Spotlight finds it.

Press ⌘7 (Window &gt;&gt; Monitor) to monitor the traffic on your Airport Adapter.




Press ⌘6 (Windows &gt;&gt; Sniff) to put the Airport card into &quot;Sniff&quot; mode.  Select your channel and start sniffing...


It will then start sniffing the network packets...When it's done, it will put a .wcap file on your desktop.  You can then use the file with Wireshark or with the tcpdump command.