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5 Firewall Best Practices for SMEs and Large-Enterprises in '24

Updated on Mar 14
6 min read
Written by
Cem Dilmegani
Cem Dilmegani
Cem Dilmegani

Cem is the principal analyst at AIMultiple since 2017. AIMultiple informs hundreds of thousands of businesses (as per Similarweb) including 60% of Fortune 500 every month.

Cem's work focuses on how enterprises can leverage new technologies in AI, automation, cybersecurity(including network security, application security), data collection including web data collection and process intelligence.

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Researched by
Ezgi Alp
Ezgi Alp
Ezgi Alp
Ezgi is an industry analyst at AIMultiple. She specializes in firewalls and firewall management.

She has held various positions in academia and the finance industry. Ezgi holds a PhD in finance and a bachelor's degree in management. She has a background in publishing scientific articles and presenting at conferences.

• Tanyeri A. B., and Alp E. (2022).
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5 Firewall Best Practices for SMEs and Large-Enterprises in '245 Firewall Best Practices for SMEs and Large-Enterprises in '24

Firewalls play a crucial role in safeguarding networks against cyber threats, and implementing firewall best practices is essential for robust security. Organizations in search of firewall audit software may find valuable insights in this article on firewall audit software comparison.

The specific requirements pertaining to firewall security may vary across small and medium-sized enterprises (SMEs), and large enterprises. Here’s a detailed guide covering key firewall best practices tailored to the distinct needs of each business size category.

This image shows a firewall best practices defending the network.

1. Define security policies and objectives

Before delving into firewall deployment and configuration, one of the first firewall best practices is to define clear security policies and objectives. This involves conducting a thorough risk assessment to identify potential vulnerabilities and establish overarching security goals. Firewall policies should encompass firewall rules and guidelines governing network access, data protection, and incident response protocols.

Security policy should be tailored to address specific regulatory mandates, such as data protection requirements outlined in GDPR or the healthcare privacy and security provisions mandated by HIPAA. These policies serve as a roadmap for implementing appropriate security controls, including user access management, data encryption, and incident response procedures, to ensure compliance with regulatory standards.

1.1. Large enterprises

For large enterprises, defining security policies involves navigating a complex landscape of regulatory requirements such as GDPR, HIPAA, or PCI DSS. These regulations dictate specific measures for data protection, privacy, and compliance, necessitating meticulous policy development to address each mandate adequately.

1.2. Small and medium-sized enterprises

In contrast, SMEs may encounter less stringent regulatory obligations but still need to formulate security policies tailored to their unique operational needs and risk profiles. While compliance with industry standards and regulations remains important, SMEs may prioritize flexibility and scalability in their policies to adapt to evolving potential security threats and business environments.

2. Choose the type of firewall

As a second firewall best practices, selecting the appropriate type of firewall is crucial in aligning with the organization’s security requirements and operational needs.

2.1. Types of firewalls by deployment

The three main types of firewalls by deployment include hardware firewalls, software firewalls, and Firewall as a Service (FWaaS). While hardware firewalls offer robust perimeter protection, software firewalls provide flexibility and scalability, and FWaaS offers the convenience of cloud-based security management. Organizations should consider the following categories:

2.1.1. Hardware firewall

It is a physical device positioned between a computer or network and its internet connection. This type of firewall actively analyzes data packets to identify and block threats, providing robust protection against cyber intrusions. Hardware firewalls, once implemented, require all internet traffic to pass through them, making decisions based on predefined security policies.

Ideal for large enterprises with complex network infrastructures, hardware firewalls offer high-performance filtering capabilities and can handle heavy traffic loads efficiently. 

2.1.2. Software firewall

Software firewalls, including virtual, container, and managed service firewalls, protect sensitive data, workloads, and applications in environments where deploying physical firewalls is challenging or impossible. They provide device-level protection by installing firewalls directly on individual computers or devices.

Suited for SMEs and organizations with limited IT resources, software firewalls provide cost-effective security solutions that can be installed on individual devices or servers. They offer granular control over network traffic and are easily configurable to meet specific security requirements.

2.1.3. Firewall as a service (FWaaS)

FWaaS provides cloud-based network traffic inspection, enabling organizations to augment or decommission on-premises network firewall appliances. It helps reduce the management burden on in-house security staff. Increasingly popular among businesses of all sizes, FWaaS delivers firewall functionality through cloud-based services. This model offers scalability, flexibility, and centralized management, making it an attractive option for dynamic and distributed environments.

2.2. Types of firewalls by operation

This section categorizes firewalls based on their specific functionalities and operational mechanisms, providing insights into how they inspect and regulate network traffic to enforce security policies.

2.2.1. Packet-filtering firewall

Packet-filtering firewall inspects individual packets of data and makes decisions based on predefined rules. While they are efficient for basic traffic filtering based on attributes such as source and destination IP addresses, port numbers, and protocols, they lack the advanced features and visibility offered by other firewall types.

2.2.2. Circuit-level gateway

Circuit-level gateway operates at the session layer of the OSI model and establishes connections based on session information. It validates handshaking processes for TCP and UDP connections, ensuring secure communication between network nodes. They provide enhanced security for remote access scenarios but may not offer granular control over network traffic.

2.2.3. Stateful firewall

Stateful firewall maintains state information about active connections, allowing them to make context-aware decisions based on the connection’s state. It offers improved security and performance compared to packet-filtering firewall by analyzing traffic at the network and transport layers.

2.2.4. Proxy firewall

Proxy firewall acts as an intermediary between internal systems and external servers, filtering messages to prevent unauthorized access. It intercepts and inspects traffic before forwarding it to its destination. Proxy firewall provides advanced filtering capabilities and enhances security by masking the client’s IP address.

2.2.5. Next-generation firewall

Next-generation firewall integrates traditional firewall features with advanced security functionalities such as intrusion detection and prevention, application control, and SSL inspection. It offers comprehensive protection against modern threats and is well-suited for large enterprises with complex security requirements.

3. Start firewall configurations

Given that the misconfiguration of the security management system is the primary cause of 99% of firewall security breaches, ensuring effective firewall configuration is crucial for successful protection against potential security threats1.

3.1. Employ a default deny policy

Adopting a default deny policy ensures that only explicitly allowed traffic is permitted, minimizing the attack surface and reducing the risk of unauthorized access. This approach forces organizations to define explicit rules for inbound and outbound traffic, enhancing control and visibility.

3.2. Follow the principle of least privilege

The principle of least privilege dictates that users should only be granted the minimum level of access necessary to perform their job functions. By restricting access rights and permissions to essential resources, organizations can mitigate the risk of insider threats and unauthorized access attempts.

3.3. Implement network segmentation

Network segmentation involves dividing the network into distinct segments or zones based on security requirements and business functions. This practice helps contain breaches, limit lateral movement, and reduce the impact of security incidents by isolating critical assets and sensitive data.

3.4. Conduct Firewall Audits

Regular firewall audits are essential for evaluating the effectiveness of firewall configurations, identifying security vulnerabilities, and ensuring compliance with industry regulations. By reviewing firewall logs, analyzing network traffic, and performing penetration testing, organizations can proactively detect and mitigate security threats.

3.5. Establish an Incident Response Plan

An incident response plan outlines the procedures and protocols to be followed in the event of a security incident or data breach. It defines roles and responsibilities, escalation procedures, and communication protocols to facilitate a coordinated response and minimize the impact of security incidents on business operations.

4. Leverage an automated firewall audit tool

Automated firewall audit tools are designed to streamline the arduous task of auditing firewall configuration, leveraging advanced algorithms and machine learning algorithms to automate the monitoring, analysis, and management of firewall settings. By integrating with existing network security infrastructure, automated firewall audit tools provide a comprehensive view of firewall rules configuration, logs, and network traffic, allowing security teams to identify and rectify vulnerabilities in real time.

Moreover, automated security audit tools generate detailed security audit reports, providing valuable insights into firewall performance, security events, and potential threats.

4.1. Large enterprises

Leveraging an automated firewall audit tool can be particularly advantageous for larger organizations with complex network infrastructures and a higher volume of network traffic. These organizations often have more extensive firewall configurations and face greater challenges in ensuring continuous compliance and security. Automated tools can help streamline the process of monitoring and managing firewall configuration, providing real-time insights and identifying potential security risks more efficiently.

4.2. Small and medium-sized enterprises

Smaller organizations with simpler network environments may also find value in automated firewall audit tools, especially if they lack dedicated IT resources for manual monitoring and management. Ultimately, the decision to leverage such tools should be based on the organization’s specific needs, resources, and security requirements.

5. Perform regular security assessments

Continuous security assessments of firewall configurations and rules involve ongoing monitoring, analysis, and optimization of firewall configurations to adapt to evolving security threats and compliance requirements.

Implementing security patches and updates promptly enables to address newly discovered vulnerabilities and ensures that firewall settings remain aligned with the organization’s security policies and objectives. By leveraging automated tools and conducting regular security audits, organizations can maintain continuous compliance, improve network performance, and enhance overall security posture.


How often should firewall policies be reviewed?

While best practice suggests an annual review, the frequency may vary based on factors such as organizational risk tolerance and regulatory requirements. Automated tools can streamline the review process and provide real-time monitoring to promptly address any misconfigurations or emerging threats.

How many firewalls should an organization have?

The number of firewalls required depends on various factors such as the size of the network, its complexity, the level of security required, and regulatory compliance needs. Smaller organizations may suffice with one or two firewalls, while larger enterprises with extensive networks may require several distributed firewalls to adequately protect their infrastructure. It’s essential to conduct a thorough assessment of the network architecture and security requirements to determine the appropriate number of firewalls needed for optimal protection.

Further reading

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Cem Dilmegani
Principal Analyst
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Cem Dilmegani
Principal Analyst

Cem is the principal analyst at AIMultiple since 2017. AIMultiple informs hundreds of thousands of businesses (as per Similarweb) including 60% of Fortune 500 every month.

Cem's work focuses on how enterprises can leverage new technologies in AI, automation, cybersecurity(including network security, application security), data collection including web data collection and process intelligence.

Cem's work has been cited by leading global publications including Business Insider, Forbes, Washington Post, global firms like Deloitte, HPE, NGOs like World Economic Forum and supranational organizations like European Commission. You can see more reputable companies and media that referenced AIMultiple.

Cem's hands-on enterprise software experience contributes to the insights that he generates. He oversees AIMultiple benchmarks in dynamic application security testing (DAST), data loss prevention (DLP), email marketing and web data collection. Other AIMultiple industry analysts and tech team support Cem in designing, running and evaluating benchmarks.

Throughout his career, Cem served as a tech consultant, tech buyer and tech entrepreneur. He advised enterprises on their technology decisions at McKinsey & Company and Altman Solon for more than a decade. He also published a McKinsey report on digitalization.

He led technology strategy and procurement of a telco while reporting to the CEO. He has also led commercial growth of deep tech company Hypatos that reached a 7 digit annual recurring revenue and a 9 digit valuation from 0 within 2 years. Cem's work in Hypatos was covered by leading technology publications like TechCrunch and Business Insider.

Cem regularly speaks at international technology conferences. He graduated from Bogazici University as a computer engineer and holds an MBA from Columbia Business School.

Sources: Traffic Analytics, Ranking & Audience, Similarweb.
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Hypatos gets $11.8M for a deep learning approach to document processing, TechCrunch.
We got an exclusive look at the pitch deck AI startup Hypatos used to raise $11 million, Business Insider.

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