The definition of a firewall is a security gate for your computer. When it is installed, it analyzes incoming data and allows certain information to pass through if that information is safe and trusted. If information is not trusted or if something tries to pass through that does not belong, then the firewall stops it in its tracks.
Function of a Firewall
- A firewall is an installed feature on a computer network that has access to the Internet. Firewalls are basically named after their function, as they work as a digital blocker for harmful material trying to enter a network from the Internet. Firewalls monitor information in and out of your computer to make sure that only safe information reaches your computer.
- Every website on the Internet carries with it a signature, and sends out information in what are known as packets. These packets contain data that is coded in a manner that is either trusted or distrusted by the firewall settings, depending on the parameters set by the user.
- If the packets contain data profiles that aren’t programmed to be trusted by the firewall, the trusted information is allowed to access the network but all of the distrusted content is blocked and discarded.
How a Firewall Works
- The firewall filter siphons all of the coded information as it gets to the firewall, deciphering the coded information and identifying any codes or programming anomalies that may represent a threat to the system.
- The firewall seeks these distrusted codes out of the packet information and then checks them against the system parameters to determine whether or not to allow the information through the firewall.
- The firewall works in order to keep websites that pose a threat to the network from accessing the network or any information contained within it.
- Firewalls often are the first line of defense in many Internet-based systems, acting as a filter for flagged items. If the information entering the network has any flagged coding in its signature, the firewall prevents the information from entering the network.
Getting a Firewall
- Most operating systems contain a firewall within them, especially those that include a web browser program, or those that are designed to work in business formats.
- Home networks, whether they have broadband or wired Internet connections, are also vulnerable to harmful websites and the damage they can inflict, so home users also need protection from a firewall.
- Firewalls can be purchased in the form of either computer software programs or physical hardware devices which are installed or incorporated into Internet-based systems.
An example of a firewall is blocking particular domain names from sending data into your home network - such as, if you and your family are diehard Boston Red Sox fans, you could technically block all traffic from nyyankees.com from entering your home.
firewall definition by American Heritage Dictionary
- A fireproof wall used as a barrier to prevent the spread of fire.
- Computer Science Any of a number of security schemes that prevent unauthorized users from gaining access to a computer network or that monitor transfers of information to and from the network.
firewall - Business Definition
firewall - Computer Definition
Security software that can actively block unauthorized entities from gaining access to internal resources such as systems, servers, databases, and networks. A firewall may also act to prevent internal users from accessing unauthorized external resources. A firewall is installed in a communications router, server, or some other device that physically and/or logically is a first point of access into a networked system. A packet-filtering firewall examines all data packets, forwarding or dropping individual packets based on predefined rules that specify where a packet is permitted to go, in consideration of both the authenticated identification of the user and the originating address of the request. A proxy firewall acts as an intermediary for user access requests by setting up a second connection to the resource. The proxy then decides if the message or file is safe. A stateful inspection firewall examines packets, notes the port numbers that they use for each connection, and shuts down those ports once the connection is terminated. See also authentication, authorization, proxy firewall, and security.
A computer program or hardware device used to provide additional security on networks by blocking access from the public network to certain services in the private network. Firewalls contain rule sets that either grant or deny data traffic flowing into or out of a network. Simply put, firewalls are to the perimeter of a network what a moat and wall are to a castle.
Because system administrators need to grant access from the outside world to some services within the perimeter, such as email or a Web server, they need to drill holes for these services in their firewalls. Unfortunately, these holes can be exploited by perpetrators. For example, control of outgoing traffic is an often neglected area; there is a real risk that users can introduce malicious code into the network by opening an email attachment or by surfing to a Website having malicious content that installs a back door program on an internal system. These back doors initiate connections to an attacker that, from the firewall’s perspective, seem to be coming from “inside” and are therefore allowed. The reality is that back doors can allow attackers to take over control of an internal system and create considerable damage.
The primary method for keeping a computer secure from intruders. A firewall allows or blocks traffic into and out of a private network or the user's computer. Firewalls are widely used to give users secure access to the Internet as well as to separate a company's public Web server from its internal network. Firewalls are also used to keep internal network segments secure; for example, the accounting network might be vulnerable to snooping from within the enterprise. In the home, a personal firewall typically comes with or is installed in the user's computer (see Windows Firewall). Personal firewalls may also detect outbound traffic to guard against spyware, which could be sending your surfing habits to a Web site. They alert you when software makes an outbound request for the first time (see spyware). In the organization, a firewall can be a stand-alone machine (see firewall appliance) or software in a router or server. It can be as simple as a single router that filters out unwanted packets, or it may comprise a combination of routers and servers each performing some type of firewall processing. For more about the various firewall techniques, see firewall methods.
firewall - Cultural Definition
A means of separating a computer network from outside networks for security purposes. A server outside an organization's own network may be used to funnel all incoming and outgoing traffic to assist in keeping out viruses, as well as to prevent unauthorized outsiders from gaining access to a network.
firewall - Science Definition
Variant of fire wall
- a fireproof wall to prevent the spread of fire, as from one room or compartment to the next
- anything serving as a protective barrier; specif., a program or system designed to protect a computer network from unauthorized access, as over the Internet