A personal firewall is an application which controls

network Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics ...

traffic to and from a computer, permitting or denying communications based on a

security policy Security policy is a definition of what it means to ''be secure'' for a system, organization or other entity. For an organization, it addresses the constraints on behavior of its members as well as constraints imposed on adversaries by mechanisms ...

. Typically it works as an

application layer firewall An application firewall is a form of firewall that controls input/output or system calls of an application or service. It operates by monitoring and blocking communications based on a configured policy, generally with predefined rule sets to c ...

. A personal firewall differs from a conventional

firewall Firewall may refer to: * Firewall (computing), a technological barrier designed to prevent unauthorized or unwanted communications between computer networks or hosts * Firewall (construction), a barrier inside a building, designed to limit the spre ...

in terms of scale. A personal firewall will usually protect only the computer on which it is installed, as compared to a conventional firewall which is normally installed on a designated interface between two or more networks, such as a router or

proxy server In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource. Instead of connecting directly to a server that can fulfill a request ...

. Hence, personal firewalls allow a security policy to be defined for individual computers, whereas a conventional firewall controls the policy between the networks that it connects. The per-computer scope of personal firewalls is useful to protect machines that are moved across different networks. For example, a

laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...

computer may be used on a trusted

intranet An intranet is a computer network for sharing information, easier communication, collaboration tools, operational systems, and other computing services within an organization, usually to the exclusion of access by outsiders. The term is used in c ...

at a workplace where minimal protection is needed as a conventional firewall is already in place, and services that require open ports such as file and printer sharing are useful. The same laptop could be used at public Wi-Fi hotspots, where it may be necessary to decide the level of trust and reconfigure firewall settings to limit traffic to and from the computer. A firewall can be configured to allow different security policies for each network. Unlike network firewalls, many personal firewalls are able to control network traffic allowed to programs on the secured computer. When an application attempts an outbound connection, the firewall may block it if blacklisted, or ask the user whether to blacklist it if it is not yet known. This protects against malware implemented as an executable program. Personal firewalls may also provide some level of

intrusion detection An intrusion detection system (IDS; also intrusion prevention system or IPS) is a device or software application that monitors a network or systems for malicious activity or policy violations. Any intrusion activity or violation is typically rep ...

, allowing the software to terminate or block connectivity where it suspects an intrusion is being attempted.

Features

Common personal firewall features: * Block or alert the user about all unauthorized inbound or outbound connection attempts. * Allows the user to control which programs can and cannot access the

local network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a larger ...

and/or

Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...

and provide the user with information about an application that makes a connection attempt. * Hide the computer from port scans by not responding to unsolicited network traffic. * Monitor applications that are listening for incoming connections. * Monitor and regulate all incoming and outgoing Internet users. * Prevent unwanted network traffic from locally installed applications. * Provide information about the destination

server Server may refer to: Computing *Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients Role * Waiting staff, those who work at a restaurant or a bar attending customers and su ...

with which an application is attempting to communicate. * Track recent incoming events, outgoing events, and intrusion events to see who has accessed or tried to access your

computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as C ...

. * Blocks and prevents hacking attempt or attack from hackers.

Limitations

Firewalls help protecting internal network from

hackers A hacker is a person skilled in information technology who uses their technical knowledge to achieve a goal or overcome an obstacle, within a computerized system by non-standard means. Though the term ''hacker'' has become associated in popu ...

, However firewall do have some limitations. * If the system has been compromised by

malware Malware (a portmanteau for ''malicious software'') is any software intentionally designed to cause disruption to a computer, server, client, or computer network, leak private information, gain unauthorized access to information or systems, depri ...

spyware Spyware (a portmanteau for spying software) is software with malicious behaviour that aims to gather information about a person or organization and send it to another entity in a way that harms the user—for example, by violating their privac ...

or similar software, these programs can also manipulate the firewall, because both are running on the same system. It may be possible to bypass or even completely shut down software firewalls in such a manner. * A firewall can't notify, if it has been incorrectly configured. * Firewall may limit access from the Internet, but it may not protect your network from wireless and other access to your systems. * Firewalls and

Virtual Private Networks A virtual private network (VPN) extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. The be ...

are not the only solution to secure private documents and emails that are either sent within an organization or to other business contacts that are outside the organization. * The alerts generated can possibly desensitize users to alerts by warning the user of actions that may not be malicious. *

Software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ...

firewalls that interface with the operating system or with other firewalls or

security software Computer security software or cybersecurity software is any computer program designed to influence information security. This is often taken in the context of defending computer systems or data, yet can incorporate programs designed specifically ...

at the kernel mode level may potentially cause instability and/or introduce security flaws.

History

In the mid 1990s, as a part of the information security architecture project for a Fortune 100 corporation in the United States (the Anheuser-Busch Corporation), one of the members of the three-man architectural development team came up with a concept with regards to improving the overall security of the operating system to be used on all the computers within this networked system (a network system referred to as BudNET). Improving the overall security of an operating system is commonly referred to as "OS Hardening." The member of the team that was charged with this was SSgt. Donald R. Woeltje Jr. and the concept he came up with was the installation of special software (firewall software) on every BudNET server, workstation, and perimeter security device. Indeed, every single Windows system on the BudNET network. This is a concept that is now commonly referred to as "personal firewall" software. So, while SSgt. Woeltje did not invent personal firewall software, he did invent the idea of the "personal firewall." Evidence of this fact exists in the Anheuser-Busch Security Model Proposal document made by SSgt. Woeltje, at the time. When SSgt. Woeltje brought in all the leading firewall vendors for meetings concerning the products being considered for use for the perimeter security of the BudNET network, SSgt. Woeltje brought up the concept of the "personal firewall" with the vendors and asked them if they had any firewall product that could be used in this way. With the exception of the representatives from the Cyberguard Corporation, every vendor said that not only did that not have any firewall software that could be used in this way but they also said that the idea was crazy and unworkable. But, today we know they were wrong because the use of personal firewall software has become a de facto computer security standard. The companies that SSgt. Woeltje discussed "personal firewall" software with were, among others, Cisco, Checkpoint, Axent Technologies, Milkyway Networks, Cyberguard, Network ONE, Trusted Information Systems, and Secure Computing Corporation.

References

External links

Software Firewalls: Made of Straw? Part 1
an
Part 2
– explanation of design, and discussion of susceptibility on

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

computers to circumvention by a

Layered Service Provider Layered Service Provider (LSP) is a deprecated feature of the Microsoft Windows Winsock 2 Service Provider Interface (SPI). A Layered Service Provider is a DLL that uses Winsock APIs to attempt to insert itself into the TCP/IP protocol stack. Once ...

.
Software Firewall Test Rankings
Matousec, 2014 {{DEFAULTSORT:Personal Firewall Firewall software

Features

Limitations

History

See also

References

External links