Automatic proxy selection based on network location with Firefox (proxy.pac)

[Sébastien Pierrel <sebastien.pierrel@gmail.com>]

Hi all,

I'm tired of changing my proxy settings everytime I move to a
different network with my laptop. Therefore, I'm writting an automated
script (proxy.pac):

----------------------------------8<-----------------------------------
function FindProxyForURL(url, host)
{
var company_net = "x.x.x.x";
var company_mask = "255.255.255.0";

  if(isInNet(myIpAddress(), company_net, company_mask)) {
       return "PROXY proxy.company.com:8080;";
    }

return "DIRECT;";
}
----------------------------------8<-----------------------------------

well, the actual script is a *little* more complicated but this is
just enough to illustrate my problem:
isInNet(myIpAddress() always returns the loopback address (127.0.0.1)

Is that a bug from firefox? (Debian package 1.0.7-1)
How could I possibly check other interfaces' address? (lan, wlan, ppp...)

Thx,
/Seb.