Firewalls are used in businesses to prevent attacks, mitigate security issues, and provide a sense of known security to the organization. Firewall features are generally the same depending on the brand or vendor of the firewall, as they provide authorized access to only one network. This review will examine common security features found in firewalls and how they are used in day-to-day functions to help prevent problems that threaten organizations. Firewalls work by preventing unauthorized access to a network by monitoring and enabling/disabling traffic through security policies and procedures. Grimes says: “Firewalls work by inspecting and filtering packet traffic between two networks. Firewalls are classified based on the level of the Open System Interconnection (OSI) model they inspect. Most firewalls are packet filters, meaning they work at the network layer of the OSI model and make logical decisions based on the packet's IP addresses (source and destination), IP port numbers, and whether the packet is in format UDP or TCP. Circuit-level firewalls work at the transport layer of the OSI model and control host session information. Circuit-level firewalls can block packets based on host name and other IP session information such as flags and sequence numbers” (Grimes, 2003). Some recent firewalls also include auto-blocking features that help monitor network activity and automatically block an entry point (often IP address or port) which alleviates known attacks or attack patterns such as DDOS. Many firewalls now include monitoring and reporting to alert IT staff to the presence or occurrence of a problem and what steps the firewall automatically takes to prevent the problem. ...... half of the paper ...... h like viruses or tracking mechanisms and more. Newer software-based firewalls have built-in technology that helps with this type of filtering during initial implementation. McAffee's newest software firewall provides several filtering features including folder and file encryption control over traffic exchange, social network protection, and more. Other features include functionality to block questionable websites in over 35 categories, block file sharing and peer to peer network protocols, monitor encrypted site activity, and more. (McAffee, 2014). References Grimes, Roger. (2003). Types of firewall filters. Windows IT professional. http://windowsitpro.com/security/types-firewall-filtersMcAffee. (2014). http://home.mcafee.com/store/total-protectionZoneAlarm. (2014). What makes a good firewall. http://www.zonealarm.com/security/en-us/firewall/good-firewall.htm