i used this previously it knows as astaro security gateway one of awesome dedicated router/UTM you could ever have all it need is extra machine
I have a spare Intel Core 2 Duo PC which has two NIC's (Realtek Onboard NIC & Intel PCI NIC. However, I have been lazy about giving Sophos UTM a try.
Keep in mind you can use PfSense ,Zentyal onto Ubuntu and even an OpenSUSE made as gateway.You will also have a nice HTPC -Firewall box with the last 2. The only plus is the antivirus engine ,but i am not sure it works under the free stuff.I would still call it Astaro.