Squid > clients auto-detect proxy setting

[wp.rauchholz]

I am trying to setup my squid proxy in such a way that when I am at home my devices autodetect squid and when I am travelling the devices ignore it
So that is what I did:

In dhcpd.con I added
option wpad code 252 = text; (global section)
option wpad "http://<mydomain>/wpad.dat";

I placed wpad.dat into apache's root directory:

/var/www/<domain>/html
function FindProxyForURL(url, host) {
return "PROXY <domain>:3128; DIRECT";
}

In Gnome > Network > Proxy > Automatic I added: <domain>/wpad.dat.

It does not find it though. What am I doing wrong or what am I missing?

Thanks you,

Wolfgang