Computer Security – Definitions

Application-Proxy Gateway Firewall: An advanced firewall that combines lower layer access control with upper layer functionality, and includes a proxy agent that acts as an intermediary between two hosts that wish to communicate with each other.

Boundary Router: A router located at the organization’s boundary with an untrusted external network. In the context of this document, a boundary router is configured to be a packet filter firewall.

Circuit-Level Gateway: A form of [..]

Firewalls | Policies Based on Applications

Most early firewall work involved simply blocking unwanted or suspicious traffic at the network boundary. Inbound application proxies take a different approach—they let traffic destined for a particular server into the network, but capture that traffic in a server that processes it like a port-based firewall.

The application proxy approach provides an additional layer of security for incoming traffic by validating some of the traffic before it reaches the desired [..]

Network Layouts with Firewalls

The figure below shows a typical network layout with a hardware firewall device acting as a router. The unprotected side of the firewall connects to the single path labeled “WAN,” and the protected side connects to three paths labeled “LAN1,” “LAN2,” and “LAN3.” The firewall acts as a router for traffic between the Wide Area Network (WAN) path and [..]

Is it a good have 2 firewalls running simultaneously ?

We recommend that you run only one antivirus and one firewall at a time. Having more than one antivirus or firewall active in memory uses additional resources and can result in software conflicts, network and software access problems and false virus alerts. Your best defense against computer viruses and malicious programs is to keep your antivirus virus definitions up to date and update your antivirus and firewall to lasts [..]