A firewall is a computer security device that monitors incoming and outgoing network traffic and determines whether to allow or block specific traffic based on defined security rules.
A firewall can be software, hardware, or both. A software firewall is a computer program that is installed on each computer and designed to regulate traffic through port numbers and applications, while a hardware firewall is a piece of equipment installed between the user's network and gateway. It's best to have both a software and a physical firewall.
The chief purpose of a firewall is to establish a barrier between the user's internal network and incoming traffic from the Internet, blocking hackers and viruses. Traffic entering or leaving the local network to which you are connected must pass through the firewall, which examines each message and blocks those that fail to meet specified security criteria.
A firewall is the first line of defense. There are several types of firewalls, the most common being host-based and network-based. A host-based firewall is installed on individual servers, monitoring incoming and outgoing signals. Network-based firewalls may be built into the cloud's infrastructure or delivered as a virtual firewall service.
Other types of firewalls include packet-filtering firewalls, stateful inspection firewalls, proxy firewalls, and next-generation firewalls.
A packet-filtering firewall examines packets and blocks those that don't meet established security criteria while allowing those that meet the criteria to pass. There are two kinds of packet-filtering firewalls: stateful and stateless. Stateful firewalls are more secure than the stateless kind because they retain information about previously passed packets, while stateless firewalls examine each packet independently of the other, lacking context.
Packet-filtering firewalls are not able to determine if the contents of a request will have an adverse effect on the application it's reaching. Next-generation and proxy firewalls provide more security than the packet-filtering type.
Next-generation firewalls add functionality to traditional firewall technology, such as encrypted traffic inspection, antivirus protection, and other intrusion prevention systems. Unlike packet-filtering firewalls, next-generation firewalls conduct deep packet inspection, examining the data within the packet itself, allowing for more accurate detection of potentially malicious data.
Proxy firewalls filter network traffic at the application level, acting as an intermediary between two end systems. With a proxy firewall in place, the client sends a request to the firewall, where it is evaluated against a set of security rules, then either permitted or blocked.
In practice, many firewall systems use two or more of these techniques.
Firewalls are built into the macOS and Windows operating systems, and there are also third-party firewall packages, which may be offered as standalone software packages or as part of a larger security suite. Some broadband routers have firewall capabilities built-in, although these tend to be rudimentary.
Any topics relating primarily to computer network firewalls are appropriate for this category. However, software products in which a firewall is just a module should be listed in the software category most appropriate for its primary product.
Recommended Resources
Cisco Next-Generation Firewalls
Cisco Systems is a global technology corporation headquartered in San Jose, California. Its next-generation firewall systems are highlighted particularly its Firepower hardware firewall series, its next-generation virtual firewall systems, and Meraki MX series, each of which is highlighted here, including features, specifications, datasheets, demos, and comparisons with other products. Its next-generation firewall management services and customer success stories are included.
https://www.cisco.com/c/en/us/products/security/firewalls/
Comodo is a cybersecurity corporation based in Clifton, New Jersey, but with global operations. Compatible with Microsoft Windows operating systems, the Comodo Firewall monitors inbound and outbound network traffic, checking for legitimacy. It stealths the computer ports against hackers and blocks malicious software from transmitting the user’s confidential data over the Internet. A free firewall package is available, and its Internet Security Pro adds antivirus protection.
https://personalfirewall.comodo.com/
Established through Kickstarter in 2017, Firewalla is a network layer security device that offers intrusion detection and prevention, intelligent behavior analytics, and a VPN server, all packaged in a 2x2” box, managed by smartphone applications. Basically, it is a firewall with added features, which include activity and parental control, ad blocking, and safe search. Video and textual instructions, as well as screenshots, are offered for managing rules and alarms.
https://firewalla.com/
Offering Internet security products since 1999, Firewalls.com is an authorized reseller for SonicWall, Sophos, WatchGuard, and Fortinet products, and certified sales representatives and support engineers for SonicWall products. Specializing in hardware wired-only and wireless firewall products, as well as Sophos XG firewalls, the features, benefits, and pricing for each are posted, and models may be compared with other models. Datasheets may be downloaded.
https://www.firewalls.com/
Google Cloud Firewall Rules Overview
Google Cloud firewall rules let the user allow or deny traffic to and from their virtual machine based on configurations that they specify. Each Virtual Private Cloud (VPC) network functions as a distributed firewall and, while firewall rules are defined at the network level, connections are allowed or denied on a per-instance basis. Explanations, specifications, and characteristics of the rules are stated, along with a list of firewall rule components and other data.
https://cloud.google.com/vpc/docs/firewalls
Udemy is an online educational program for business and individual training in various subjects. Courses are provided entirely online and certificates are issued upon successful completion of each course. Although its course offerings are subject to change from time to time, it currently offers nearly forty courses on the subject of firewalls, including programs for people at various levels of expertise, as well as courses covering specific firewall products. Course details are posted for each.
https://www.udemy.com/topic/Firewall/
Established in 2000, and currently, under the ownership of CheckPoint Software Technologies, ZoneAlarm specializes in firewall products for home and business clients, but also offers antivirus products for the Windows operating system. Its three chief products include ZoneAlarm Free Antivirus, Pro Antivirus + Firewall, and Extreme Security, the latter of which is also available for Android and iOS devices. Its products, prices, and support services are discussed.
https://www.zonealarm.com/
