CG: n
CT: A firewall is a system designed to prevent unauthorized access to or from a private network. You can implement a firewall in either hardware or software form, or a combination of both. Firewalls prevent unauthorized internet users from accessing private networks connected to the internet, especially intranets. All messages entering or leaving the intranet (the local network to which you are connected) must pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.
S: IU – https://kb.iu.edu/d/aoru (last access: 10 December 2020)
N: 1. The first time the term appeared as fire-wall, coined in 1851 as a physical wall meant to prevent the spread of fire in a structure. Later, Computer sense (originally figurative) was coined in 1990. The term is a combination of the word’s “fire” (from Old English fyr “fire, a fire,” It had two roots: paewr– and egni– [source of Latin ignis]; the first meaning “inanimate,” referring to fire as a substance, and the latter meaning “animate,” referring to it as a living force) and “wall” (from Old English weall, and Anglian wall “rampart, dike, earthwork” [natural as well as man-made], “dam, cliff, rocky shore,” also “defensive fortification around a city, side of a building,” and form an Anglo-Frisian and Saxon borrowing from Latin vallum “wall, rampart, row or line of stakes,” apparently a collective form of vallus “stake”).
2. In computing, it acts as a barrier between a trusted system or network and outside connections, such as the Internet.
3. It can be divided as:
Hardware firewall: is that it’s a separate appliance that monitors, filters and controls the traffic entering or leaving your network. A hardware firewall can be strategically placed in a network to optimize its functionality. This type of hardware is often coupled with a router to start at the root of the input/output stream.
Software firewall: which you install on existing endpoint devices, servers, routers, on each computer, to regulate network traffic.
4. There are different types of firewall:
– Packet-filtering firewalls: examine packets and prohibit them from passing through if they don’t match an established security rule set. This type of firewall checks the packet’s source and destination IP addresses.
– Circuit-level gateway: provides session-level control over network traffic. Similar in operation to packet filtering routers, circuit-level gateways operate at a higher layer of the Open Systems Interconnection (OSI) reference model protocol stack.
– Application-level gateway or application gateway (ALG): is a firewall proxy which provides network security. It filters incoming node traffic to certain specifications which mean that only transmitted network application data is filtered.
– Packet-filtering firewalls: are divided into two categories: stateful and stateless. Stateless firewalls examine packets independently of one another and lack context, making them easy targets for hackers.
– Next-generation firewalls (NGFW): combine traditional firewall technology with additional functionality, such as encrypted traffic inspection, intrusion prevention systems, anti-virus, and more.
– Proxy firewalls: filter network traffic at the application level. Unlike basic firewalls, the proxy acts an intermediary between two end systems.
– Network address translation (NAT) firewalls: allow multiple devices with independent network addresses to connect to the internet using a single IP address, keeping individual IP addresses hidden. As a result, attackers scanning a network for IP addresses can’t capture specific details, providing greater security against attacks.
– Stateful multilayer inspection (SMLI) firewalls: filter packets at the network, transport, and application layers, comparing them against known trusted packets.
5. The predecessors to firewalls for network security were the routers used in the late 1980s to separate networks from one another. A network misconfiguration which caused problems on one side of the router was largely isolated from the network on the other side.
The Digital Equipment Corporation’s (DEC) firewall by Paul Vixie and further extended by Marcus Ranum when it became the Securing External Access Link (SEAL) was the first commercial firewall.
S: 1. OED – https://www.etymonline.com/word/firewall#etymonline_v_33178 (last access: 9 December 2020). 2. TT – https://techterms.com/definition/firewall (last access: 9 December 2020). 3. SB – https://securityboulevard.com/2020/10/what-is-a-firewall-definition-types-business-uses/ (last access: 9 December 2020). 4. NE – https://networkencyclopedia.com/circuit-level-gateway/ (last access: 10 December 2020); Techopedia – https://www.techopedia.com/definition/4189/application-gateway (last access: 10 December 2020); SB – https://securityboulevard.com/2020/10/what-is-a-firewall-definition-types-business-uses/ (last access: 10 December 2020). 5. OSTEC – https://ostec.blog/en/perimeter/firewall/(last access: 10 December 2020); UNM – https://www.cs.unm.edu/~treport/tr/02-12/firewall.pdf (last access: 10 December 2020).
OV: fire wall
S: TERMIUM PLUS – https://www.btb.termiumplus.gc.ca/tpv2alpha/alpha-eng.html?lang=eng&i=1&srchtxt=firewall&codom2nd_wet=1#resultrecs (last access: 10 December 2020)
SYN: network firewall, electronic firewall.
S: GDT – http://www.granddictionnaire.com/ficheOqlf.aspx?Id_Fiche=1299082 (last access: 12 December 2020)
CR: antivirus, computer network, computer science, Internet, software.
