Firewalls are a critical element in network security, designed to regulate internet traffic entering or leaving a private network or occurring within it. Whether in the form of software or a combined hardware-software unit, a firewall allows or blocks data packets based on pre-defined security rules.
Its primary function is to protect networks from unauthorized access and malicious activities, ensuring that both internal and external interactions over the internet remain secure. By doing so, firewalls play a central role in safeguarding sensitive data confidentiality and integrity within private networks.
What are Firewalls?
Firewalls act as fortified boundaries or gates that manage the flow of permitted and restricted online activity within a private network. The term "firewall" refers to the physical concept of walls used to slow the spread of fire until emergency services can extinguish it. Likewise, firewalls in networking aim to control internet traffic and slow the spread of online threats.
Firewalls are created to direct internet traffic, where it is reviewed based on a set of programmed criteria, and actions are taken accordingly. Some firewalls track traffic and communications in audit logs to record what was allowed or blocked.
A firewall is used to protect the boundaries of a private network or the devices connected to it. Thus, firewalls are a security tool within the broader category of user access control mechanisms. These barriers are set up on designated computers within the network or on users' computers and other endpoints.
How Do Firewalls Work?
Firewalls protect computers or networks from unwanted incoming or outgoing traffic. They can also examine and record all data packets in network traffic before permitting them to enter a more secure environment.
Whether it’s a physical device or software running to secure a corporate network or personal computer, the firewall is a key component of network security. For example, a firewall might protect against internal threats in a portion of the network or serve as a barrier against external threats at the network perimeter.
Firewalls act as the first line of defense in your organization, monitoring and filtering all network traffic, including outbound traffic, application-level traffic, online transactions, communications, and network connections. It blocks incoming threats based on a set of pre-programmed rules, which may also define which users can access specific areas of the network.
Types of Firewalls
There are various types of firewalls that use different filtering methods. Each type has been developed to outperform its predecessors, with many core techniques being shared across generations. Firewall types differ based on:
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Connection tracking: How the connection’s status is monitored from start to finish.
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Filtering rules: Defining the policies for allowing or blocking data traffic.
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Audit logs: Storing information about data traffic and connections for later auditing.
Each firewall type operates at a different layer of the OSI (Open Systems Interconnection) model, which helps understand how each firewall handles communications on a particular network.
Firewall Types
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Static Packet-Filtering Firewall: Known also as "Stateless Inspection Firewalls," these firewalls operate at Layer 3 of the OSI model (Network Layer). They provide basic filtering by examining each individual data packet sent across the network based on its source and destination. However, these firewalls do not track previous connections, meaning each new connection must be approved with each new data packet sent.
Filtering is based on IP addresses, ports, and packet protocols, preventing two networks from connecting directly without permission. Static filtering requires continuous manual review to be effective, which is manageable in smaller networks but becomes challenging in larger networks. These firewalls cannot read application protocols, meaning they offer limited protection.
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Stateful Inspection Firewall: Stateful inspection firewalls, also known as dynamic firewalls, differ from static firewalls in their ability to track active connections and store information about previous connections.
These firewalls function at Layer 4 of the OSI model and are capable of monitoring various layers, including Layer 7 (the Application Layer). They allow or block traffic based on technical characteristics such as packet protocols, IP addresses, and ports. These firewalls track connections using a state table, offering more granular filtering.
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Proxy Firewall: Proxy firewalls, also known as application-level firewalls (Layer 7), are unique in their ability to read and filter application protocols.
Filtering relies on application-level data instead of merely IP addresses, ports, and packet protocols. This enables deeper inspection of many different data protocols. The firewall reviews incoming data, and if no issues are detected, it allows the data to pass to the user.
This intensive security results in some delays in functionality as benign incoming data might be unnecessarily interrupted.
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Next-Generation Firewall (NGFW): As advanced threats demand more robust solutions, next-generation firewalls stay at the forefront by integrating traditional firewall features with intrusion prevention systems (IPS).
NGFWs are designed to examine and identify threats like advanced malware. These firewalls are commonly used by enterprises and advanced networks to provide comprehensive filtering solutions and protection against evolving threats.
What Do Firewalls Do in Security?
In network security, the firewall concept is designed to minimize the attack surface by consolidating access to a single entry point. Rather than exposing each device on the network directly to the internet, all traffic is routed through the firewall first.
Firewalls work both ways, filtering and blocking unauthorized traffic, whether inbound or outbound. They are also used to create audit logs of connection attempts to the network.
Some specialized uses of firewalls include:
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Malicious Intrusion Prevention: Firewalls can block unwanted connections from abnormal sources, helping prevent eavesdropping and advanced persistent threats (APTs).
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Parental Controls: Parents can block their children from accessing explicit online content.
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Workplace Internet Restrictions: Employers can prevent employees from using company networks to access certain online services or content, such as social media.
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National Internet Censorship: Governments may block citizens from accessing online content and services that oppose state leadership or values.
Firewall Solutions from Modn
Modn offers advanced network security solutions through its firewall services, providing cutting-edge technologies to protect networks from both external and internal threats.
Modn ensures that clients' networks are safeguarded by the latest firewall systems, effectively monitoring and filtering network traffic. Whether you have a large corporate network or need protection for personal computers, Modn provides customizable firewalls that allow you to adjust security rules according to your needs.
Modn’s firewalls prevent advanced threats like malware and persistent attacks, ensuring secure online transactions and sensitive communications.
With Modn’s security solutions, clients can focus on growing their business without worrying about cyber risks. Modn works to secure every part of your network, whether online or within the workplace environment.
Conclusion
Firewalls are essential in protecting networks from the growing cyber threats. They help prevent unauthorized access and protect systems from malicious attacks by filtering and monitoring all data exchanged across the network.
A firewall is your first line of defense in a world filled with security challenges, whether for businesses or individuals. A firewall ensures a safe and stable network environment, providing the necessary protection against cyber risks and offering peace of mind.