said by MaynardKrebs:There has been a competent software firewall built into Windows since one of the service packs of XP (SP2, I think it was). It will ask for permission the first time any app attempts to make an outbound connection.
A router may not stop malware from getting onto your computers, but a decent firewall on your computer (properly configured) may help prevent malware from communication to the outside world. At the very least a software firewall will alert you to the presence of some malware.
Developer: Tomato/MLPPP, Linux/MLPPP, etc »fixppp.org