Proxy auto-configuration, Mozilla

Can anybody give me instructions as to how to tell Mozilla “If you can resolve the name via DNS, then direct-connect, otherwise use this proxy server?”

I’ve got a laptop that I take from home (direct connection to the internet) to work (behind proxy/firewall), and I’m getting sick of changing the settings on my browser. I suppose I could just set up a different profile, but I think that that would end up bugging me more.


I don’t know of a way to do it automatically, but you could try using The Proxomitron. It’s a local machine proxy server, resides in your task bar, and you can figure it to work with your work’s proxy. You still have to tell it to use a proxy server or not, but it’s a LOT quicker than going into Mozilla’s preferences and doing so.

As an added benefit, you can have it filter virtually anything, and it’ll work independently of your browser’s filtering capabilities. So when you have to dump Mozilla for some of the MS-centric sites that just don’t work properly without MSIE, your filtering settings still work.

I think it’s working now, I’ll know for sure when I get home, but if I make my proxy.pac file look like this:

function FindProxyForURL(url,host)
        if (shExpMatch(myIpAddress(), "MY_WORK_SUBMASK"))
            return "PROXY";
            return "DIRECT";

and then set the proxy configuration to “auto” and point it at that file, it works at work. And I think it’ll work at home over the wireless. What I’m not at all sure about is if it will work while I’m at home and VPNed in to work. I tried saying “if the address is resolvable, then direct, otherwise proxy”, but that was always trying direct.

Does anybody know anything about pac files, that can suggest something better?


Have you visited yet? There you’ll find the forums the Mozilla folks hang out in.