tailieunhanh - Firewall Taxonomy

Firewall Taxonomy Firewalls come in various sizes and flavors. The most typical idea of a firewall is a dedicated system or appliance that sits in the network and segments an "internal" network from the "external" Internet | Firewall Taxonomy Firewalls come in various sizes and flavors. The most typical idea of a firewall is a dedicated system or appliance that sits in the network and segments an internal network from the external Internet. Most home or SOHO networks use an appliance-based device for broadband connectivity that includes a built-in firewall. In general firewalls can be categorized under one of two general types Desktop or personal firewalls Network firewalls The primary difference between these two types of firewalls simply boils down to the number of hosts that the firewall protects. Within the network firewall type there are primary classifications of devices including the following Packet-filtering firewalls stateful and nonstateful Circuit-level gateways Application-level gateways The preceding list describes general classes of firewalls but as discussed later many network firewalls represent hybrids of the preceding classifications. Many firewalls have characteristics that place them in more than one classification. Figure 2-1 shows a breakdown of the various firewall types currently available. This figure does not provide complete details of the various capabilities within each firewall type but rather shows the general taxonomy of the different firewalls available in the two primary types personal desktop firewalls and network firewalls. Figure 2-1. Firewall Taxonomy View full size image Given these various firewall types available users may have a hard time identifying exactly what they need. In many cases costs represent a driving factor in the purchase of a firewall but knowing which types of firewalls are available and what capabilities they provide helps users make a more informed final decision. Personal Firewalls Personal firewalls are designed to protect a single host from unauthorized access. Over the years this has evolved so that modern personal firewalls now integrate additional capabilities such as antivirus software monitoring and in some cases .