Mac – How to monitor network traffic in an all Mac home network

Here is an Applescript and shell script to check if Airport is connected and if not to connect it.

if (do shell script "networksetup -getinfo Wi-Fi | grep -c 'IP address:'") = 1 then
    do shell script "networksetup -setairportnetwork en1 <networkName> <passwordToNetwork>"
end if

#!/bin/bash
if [ $(networksetup -getinfo Wi-Fi | grep -c 'IP address:') = '1' ]
then networksetup -setairportnetwork en1 <networkName> <passwordToNetwork>
fi

Replace <networkName> with the network's name and <passwordToNetwork> with its password. The "en1" should be correct if you have not changed your Network devices.

Now all you need to do is loop this or call it to check the connection.

Nevertheless airport should automatically reconnect if the connection is lost. Maybe try resetting all network preferences and see if that works.

How to completely reset your Network Preferences: Turn Airport off. Close System Preferences. Navigate to: /Library/Preferences/SystemConfiguration/ Make a copy, then delete the following files:

com.apple.airport.preferences.plist
com.apple.network.*
com.apple.smb.server.plist
NetworkInterfaces.plist

Unbelievably, here are the steps that worked:

1. In System Preferences > Network, I deleted the "Wi-Fi" entry from the list of network interfaces on the left-hand side of the window.
2. I then re-added it.
3. I then selected "Join Other Network" in the "Network Name" drop-down, and entered the Network Name and WPA2 Personal password of the network.

Now the MacBook Pro seems to be happily connected to the 802.11g network, just like the iPhone and the Windows 7 Mac mini.

(I had previously trashed com.apple.airport.preferences and NetworkInterfaces.plist in /Library/Preferences/SystemConfiguration/ and restarted the machine. No idea if that had any bearing on things, but I still had the problem until I went through the steps above.)