WPAD file

Here is how our WPAD look:

function FindProxyForURL(url,host)
{ if(isPlainHostName(host)||
dnsDomainIs(host, ".domain.se"))
return "DIRECT";
else return "PROXY proxy.domain.se:8080; DIRECT";
}

Just publish this textfile on a webserver, http://servername.domain.se/wpad.txt
and configure option 252 in your DHCP to point to this location and everything should work just fine.

browsers must be configured to "automatic detect mode"