Most traditional firewall’s can only look at ports and allow or deny traffic. In today’s world, most vendors are now writing applications that use port 80 or port 443 and the traditional firewall has a hard time keeping your network secure. An application firewall can look at port 80 traffic and stop things such as Facebook Chat, but still allow Facebook. They can also look into 443 traffic and do the same thing. It might be time to update your Firewall.