Changes

A '''firewall''' is a system which filters network activity and permits presumably safe [[internet]]/intranet traffic while blocking suspicious or unwanted communication.<ref>https://en.oxforddictionaries.com/definition/firewall</ref> There are several types of firewall and methods of filtering.

A '''firewall''' is a system which filters network activity and permits presumably safe [[internet]]/intranet traffic while blocking suspicious or unwanted communication.<ref>“Definition of firewall in English by Oxford Dictionaries.” Oxford Dictionaries | English, Oxford Dictionaries, en.oxforddictionaries.com/definition/firewall. Accessed 6 Sept. 2017. </ref> There are several types of firewall and methods of filtering.

==Physical and Virtual==

==Physical and Virtual==

===Software===

===Software===

Software firewalls are not typically considered a good first line of defense, but a good addition to a tiered defense system.  They digitally intercept and attempt to analyze traffic on the client's system. Since this kind of firewall operates on the [[OSI model]]'s application layer, it has an easier time of understanding what the communication link is being used for. Additionally, this host firewall filters traffic within the [[local area network]], meaning that unwanted traffic from other hosts behind the perimeter firewall can still be blocked.<ref>Https://technet.microsoft.com/en-us/library/ff602917(v=ws.10).aspx|thumbnail</ref>

Software firewalls are not typically considered a good first line of defense, but a good addition to a tiered defense system.  They digitally intercept and attempt to analyze traffic on the client's system. Since this kind of firewall operates on the [[OSI model]]'s application layer, it has an easier time of understanding what the communication link is being used for. Additionally, this host firewall filters traffic within the [[local area network]], meaning that unwanted traffic from other hosts behind the perimeter firewall can still be blocked.<ref>“Firewall Types.” TechNet, Microsoft, technet.microsoft.com/en-us/library/ff602917(v=ws.10).aspx. Accessed 7 Sept. 2017.</ref><br />

<br />

Host firewalls rely on the operating system in order to operate properly. This means that if the host system is infected or otherwise compromised, the software firewall can be prevented from blocking unwanted traffic.<ref name="WhatIsMyIPAddress.com"/>

Host firewalls rely on the operating system in order to operate properly. This means that if the host system is infected or otherwise compromised, the software firewall can be prevented from blocking unwanted traffic.<ref name="WhatIsMyIPAddress.com"/>

<!--A disadvantage of software firewalls is that unwanted communication coming from the internet must in this case be blocked at the computer (or mobile device), so by this time, the communication has already gotten through the hardware firewall (assuming there is one). Although the attempt was still ignored, the external entity now knows there is at least one active device at that IP address.<ref name="WhatIsMyIPAddress.com">“What is a Firewall?” WhatIsMyIPAddress.com, whatismyipaddress.com/firewall. Accessed 7 Sept. 2017.</ref>-->

<!--A disadvantage of software firewalls is that unwanted communication coming from the internet must in this case be blocked at the computer (or mobile device), so by this time, the communication has already gotten through the hardware firewall (assuming there is one). Although the attempt was still ignored, the external entity now knows there is at least one active device at that IP address.<ref name="WhatIsMyIPAddress.com">“What is a Firewall?” WhatIsMyIPAddress.com, whatismyipaddress.com/firewall. Accessed 7 Sept. 2017.</ref>-->

===Stateless inspection===

===Stateless inspection===

A stateless firewall has the ability to analyze traffic and permit passage based on static values, such as the source IP address and the destination. All filtering is done by static rule sets. There are no automated processes to determine what has been requested or make any other sort of conclusion.<ref>http://www.inetdaemon.com/tutorials/information_security/devices/firewalls/stateful_vs_stateless_firewalls.shtml</ref>

A stateless firewall has the ability to analyze traffic and permit passage based on static values, such as the source IP address and the destination. All filtering is done by static rule sets. There are no automated processes to determine what has been requested or make any other sort of conclusion.<ref>“Stateful vs. Stateless Firewalls.” InetDaemon, www.inetdaemon.com/tutorials/information_security/devices/firewalls/stateful_vs_stateless_firewalls.shtml. Accessed 8 Sept. 2017.</ref>

===Stateful inspection===

===Stateful inspection===

Almost every modern computer is protected by some kind of firewall, at some point along the connection link.  Most network address translation (NAT) routers, include some form of firewall as well; even if not designed with a firewall, NAT routers can be barriers to some basic methods of attack due to the core functions of the device. The majority of networks in operation today do use NAT routers, meaning that most people are protected in this fashion.<br />

Almost every modern computer is protected by some kind of firewall, at some point along the connection link.  Most network address translation (NAT) routers, include some form of firewall as well; even if not designed with a firewall, NAT routers can be barriers to some basic methods of attack due to the core functions of the device. The majority of networks in operation today do use NAT routers, meaning that most people are protected in this fashion.<br />

Additionally, many anti-virus programs now come with a software firewall.  However, even more common than this are firewalls native to the [[operating system]]. [[Windows Firewall]], for example, is a preinstalled firewall system in all modern versions of the operating system.<br />

Additionally, many anti-virus programs now come with a software firewall.  However, even more common than this are firewalls native to the [[operating system]]. [[Windows Firewall]], for example, is a preinstalled firewall system in all modern versions of the operating system.<br />

This kind of popular protection is far better than nothing, but to ensure a network or device is secure, firewalls should not be as much of an add-on or an after-thought as a deliberate security measure.  When attacking a Windows device, the attacker knows for certain that they will need to circumvent the native firewall—therefore part of the standard attack planning includes a method to get around or through that firewall.  Some people say that windows firewall is a very good product,<ref>https://answers.microsoft.com/en-us/windows/forum/windows_7-networking/windows-7-firewall-is-it-good-enough/cc1c218a-0162-4b69-a9a9-194069d55ace</ref> while others argue that it is too trusting.<ref>https://www.cnet.com/forums/discussions/is-windows-firewall-any-good-204842/</ref>  For this reason, third-party firewalls such as the ones which sometimes come with anti-virus software are favored. For those more concerned with securing their network, a separate hardware firewall may be desired as well.  Those who do not use such a device would be well advised to ensure that their NAT router's firewall firmware is up to date.

This kind of popular protection is far better than nothing, but to ensure a network or device is secure, firewalls should not be as much of an add-on or an after-thought as a deliberate security measure.  When attacking a Windows device, the attacker knows for certain that they will need to circumvent the native firewall—therefore part of the standard attack planning includes a method to get around or through that firewall.  Some people say that windows firewall is a very good product,<ref>“ Windows 7 Firewall- Is it good enough? .” Microsoft Community, Microsoft, answers.microsoft.com/en-us/windows/forum/windows_7-networking/windows-7-firewall-is-it-good-enough/cc1c218a-0162-4b69-a9a9-194069d55ace. Accessed 8 Sept. 2017.</ref> while others argue that it is too trusting.<ref>“Is Windows Firewall Any Good??” Windows Legacy OS forum, CNET, www.cnet.com/forums/discussions/is-windows-firewall-any-good-204842. Accessed 8 Sept. 2017.</ref>  For this reason, third-party firewalls such as the ones which sometimes come with anti-virus software are favored. For those more concerned with securing their network, a separate hardware firewall may be desired as well.  Those who do not use such a device would be well advised to ensure that their NAT router's firewall firmware is up to date.

==References==

==References==