ZyXEL Communications P-312 manual Introduction to ZyXEL’s Firewall, Stateful Inspection firewalls

P312 Broadband Security Gateway

needed to filter application traffic and direct it to a number of specific systems. The router need only allow application traffic destined for the application gateway and reject the rest.

13.1.3 Stateful Inspection firewalls

Stateful Inspection firewalls restrict access by screening data packets against defined access rules. They make access control decisions based on IP address and protocol. They also "inspect" the session data to assure the integrity of the connection and to adapt to dynamic protocols. These firewalls generally provides the best speed and transparency, however, they may lack the granular application level access control or caching that some proxies support. See section 13.4 for more information on Stateful Inspection.

Firewalls, of one type or another, have become an integral part of standard security solutions for the enterprise.

13.2 Introduction to ZyXEL’s Firewall

The Prestige firewall is a stateful inspection firewall and is designed to protect against Denial of Service attacks when activated (in SMT Menu 21.2 or the Prestige Web Configurator). The purpose is to allow a private Local Area Network (LAN) to be securely connected to the Internet. The Prestige can be used to prevent theft, destruction, and modification of data as well as log events, which may be important to the security of your network. The Prestige also has packet filtering capabilities.

The Prestige is installed between the LAN and a broadband modem connecting to the Internet. This allows it to act as a secure gateway for all data passing between the Internet and the LAN.

The Prestige has one Ethernet WAN port and one Ethernet LAN port, which are used to physically separate the network into two areas.

!The WAN (Wide Area Network) port attaches to the broadband modem (Cable Modem, ADSL modem) connecting to the Internet.

!The LAN (Local Area Network) port attaches to the network of machines, which are to be secured from the outside world. These machines will have access to Internet services such as E-mail, FTP, and the World Wide Web. However, “inbound access” will not be allowed unless the remote host is authorized to use the specific service.

13-2 What Is a Firewall?