"More and more security research comes to the conclusion that personal firewalls are ineffective in controlling outbound traffic."

(sarcasm) I've never thought of that before. Wow, I guess they are right. (/sarcasm)

Kerio. IP Tables. ipfw. ipf. But that's just blocking ports -- are there any open-source outbound content compliance packages?

Personal Firewalls Ineffective at Outbound Traffic Compliance