Changing Mac OS X Snow Lepoard’s Internet Sharing IP Range

Changing the default network when using Mac OS X 10.6 internet sharing.

Internet sharing is nice. Except when the network you are sharing uses OS X’s default 192.168.2.x range (which is a silly default choice by Apple, why not use something more obscure?)

Here’s how to change it. E.g. to set it to 192.168.24.x:

# set
sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.nat NAT -dict-add SharingNetworkNumberStart 192.168.24.0

# confirm
defaults read /Library/Preferences/SystemConfiguration/com.apple.nat

The most important thing is *don’t have the settings panel open when you do this*! As it loads that file in memory and won’t read it from disk.

So close the settings panel, fiddle with defaults, and restart internet sharing.

Reference: here.