Comment 14 for bug 113201

The PAC script in question doesn't use dnsResolve(). But it does use
isResolvable() which I guess may be the culprit. Here is the PAC function

function FindProxyForURL(url, host)
{
  //So the error message "no such host" will appear through the
  //normal Netscape box - less support queries :)
  if (!isResolvable(host))
    return "DIRECT";

  if (isPlainHostName(host) ||
      dnsDomainIs(host, ".lan") ||
      dnsDomainIs(host, ".jeacocke.org.uk"))
    return "DIRECT";
  else
    return "PROXY hadron:3128; DIRECT";
}