As I suggested in SRC-13, we should write a shell script that wraps around ncutil and uses it to write out HTTP proxy settings. We should make it simple and write it in a highly defensive style, and advocate to our users that they install this script on their path with setuid root. Then, for our part, we should look to see if the script is available (perhaps adding [ulp] yet another command line argument) as well as ncutil. If we find everything we need, we use ncutil for everything. (ncutil is BSD code, and so I suppose we could just provide it ourselves, but I think installing it requires root access, and creating that setuid root script would DEFINITELY require root access; ideally, I'd like not to have to run the whole Selenium Server as root just to configure the proxy settings.) If ncutil is not available, we should fall back to using scutil + networksetup. (We should query networksetup to see if it supports configuring PAC files and use that functionality if it's available.) If networksetup isn't available, then we should fail with a link to a web page explaining our situation, like the one we've already got for Windows reg.exe issues: http://wiki.openqa.org/display/SRC/Windows+Registry+Support