Airport Card suddenly not able to get an IP address

Question

This happened all of a sudden... My wireless Internet connection was just fine, then it stopped working. It says it's connected to the wireless network, and that's true -- I verified it with the AP. But it won't get an IP address from the DHCP server. I tried clicking the "Renew DHCP Lease" button, but that doesn't do anything.
Now, I found something that does work. The following two commands entered in Terminal will fix the problem:
sudo ipconfig set en1 BOOTP
sudo ipconfig set en1 DHCP
But, if I restart my computer the problem returns.
Any ideas?

Answer 1

Try opening the Network pane of System Preferences and changing the setting to BOOTP from DHCP, saving the change, and then changing it back. The changes made by those Terminal commands are lost the next time your Internet configuration changes, which is on startup, and often on sleep. If you can't get the setting to stick from System Preferences, you can create an application which will implement the change when opened by opening the Script Editor in your /Applications/AppleScript/ folder and typing or pasting in the following:
do shell script "ipconfig set en1 BOOTP" with administrator privileges password "yourpass"
do shell script "ipconfig set en1 DHCP" with administrator privileges password "yourpass"
do shell script "sudo -k" with administrator privileges --line added to help secure your system
Give this script your password and save it as an application. When run, it will execute the Terminal commands.
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