Anthony Hoppe

We’ve recently embarked on a project to secure our wireless network. Before, we had a really simple run-of-the-mill setup using HP ProCurve 420 wireless access points. We had one SSID which would broadcast and we used a simple WEP encryption key. We decided that this wasn’t the best solution (especially since the network key was being handed out freely).

So, I started a project to set up two SSIDs. One SSID would broadcast, be a public network, and utilize a simple WEP key (too prevent just anybody from pulling up and gaining immediate Internet access). It would be set up to use VLAN tagging and all “public” traffic would only be allowed to access the Internet. The second SSID would be a private network that would not broadcast and utilize WPA encryption.

We had a LOT of trouble with WPA encryption on the ProCurve 420′s. Basically, over time, the AP’s would fail and connections would drop. It’s a problem HP is aware of and they’re supposed to release a fix someday. However, I found that setting the access points to WPA only and AES only encryption only worked (or WPA and TKIP, but AES is the ‘better’ encryption scheme).

All is fine and dandy, except for a few MacBooks. For whatever reason, they refuse to retain the wireless network settings! You reboot or put the laptop to sleep and it won’t re-connect to the network.

I’ve found that this problem is related to two things, 10.5.7 and/or the Keychain. On some MacBooks that wouldn’t retain the wireless network settings, upgrading to 10.5.8 fixed the problem. However, on others, it wasn’t this simple. I found that on some MacBooks the ‘login’ keychain had become corrupt for the user I was logged in as. For whatever reason, deleting the login keychain, any additional entries related to the SSID we want to associate with, deleting the network from the AirPort’s ‘Preferred Networks’ list, rebooting, and then re-joining the network seemed to fix it.

Though, I’m not sure if it’s a fluke. On all the machines I’ve had this problem with, I’ve prodded the ‘Preferred Networks’ list as well as every Keychain until the machine would re-connect to the correct wireless network automatically.

portfind.sh is a script I wrote to cycle the Built-In Ethernet interface on an OS X based Mac up and down.  If “spanning-tree portfast” is enabled on your switches, you should see the switch-port your computer is connected to cycle up and down.  It’s nothing fancy by any means, but it came in handy for me when trying to trace network drops to switch-ports where cable labeling was too cryptic to easily understand!

#!/bin/bash
while [ 1 ]
do
ifconfig en0 up
sleep 2
ifconfig en0 down
sleep 2
done

See, simple!

Toni and I have been trying to find a solution to publicly hosted blogs/wiki pages for our teachers.  We really liked WordPress, but there was no way I was going to manage hundreds of WordPress installations!  Then, late last week, I ran across WordPress MU!  I am so excited, it’s exactly what we were looking for!

So, this is my test blog.  It may turn into a tech tips/tricks blog some day, or it may be deleted…who knows!