Firewall (firewall) keeps Internet traffic under control, with many different filtering features, including incoming and outgoing packets of computer and network. IP filtering, port filtering, Web filtering, content filtering
Stateful Inspection Firewall follows from source to destination. Application Layer Firewall controls only the header part of the incoming and outgoing data and provides security by restricting the protocols in the application layer. For example, blocking access to a Web site over the HTTP protocol is an example. The more advanced stateful control features are those that mostly control the traffic of large networks on the Internet and the internal network. Today's firewalls are not only used for port closure. The next generation fire walls are U.T.M. (Unified Firewall, Firewall, AntiSpam, IDS / IPS, VPN, Router) are integrated devices. Although known for a period of fire wall brands U.T.M. devices claim to be cumbersome and succesful, but today all fire wall producers claim U.T.M. devices. Known U.T.M. device brands are Cisco ASA, Fortinet, Labris, Juniper, NetSafe-Unity, Netscreen, and Symantec. Ports on these devices can restrict protocol-based. It can do web filtering (banning according to categories such as terrorism, violence, weapons). It may stop operations such as downloading files. A well-established fire wall can turn a computer into a typewriter.