Pfsense is a solution capable to do multiple things . its a security , Load Balancer, Chaching , VPN Server , DNS and many more . also u can buy a hardware with installed application on it or u just need to install it on a virtual machine . the good news also amazon is now offering PFsense as a solution .
WAF ; is a common name for Web application Firewall , Lots think if you have a firewall or Intrusion prevention you are secure . well you are totally wrong web application firewall is more advance and it can detect and eliminate the following for example :
*hide / prevent developers comments and notes
*learn Web behaviors so suspected ones will be automatically blocked
Good example of best in the market are :