8 Firewall Best Practices

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Regardless of the size of your enterprise, the absence of an effective firewall exposes your enterprise network to a myriad of cyber threats. The consequences of successful cyberattacks on enterprises are becoming more expensive, not only in terms of financial losses but also in terms of brand image, reputation, business longevity and legal consequences, among others.

A well-implemented firewall provides a competent line of defense against cyber threats and other internal and external issues facing enterprise networks today.

Also see: Top Zero Trust Networking Solutions 

Why Does Your Enterprise Need a Firewall?

A firewall offers enterprises numerous benefits aside from keeping out unauthorized users. Today firewalls, especially next-generation firewalls, are keen on blocking malware and application-layer attacks. They are capable of reacting quickly and intuitively to detect and respond to attacks across enterprise networks, which are valuable qualities today when cyber threats are increasingly sophisticated and devastating.

They are also of direct benefit to the workforce. Firewalls help to better the productivity of the workplace, as they provide administrators control over incoming internet content. They can set up policies to block internet activity that impacts employee productivity.

With firewalls, organizations can limit their bandwidth for non-work-related internet usage. This may not mean completely disabling any non-work internet activity but prioritizing and reserving bandwidth for work activities and placing limits on other activities.

Another use of firewalls in the enterprise network is to protect it while working with remote employees. Remote work is becoming more common by the day, which poses a challenge to enterprises. Remote work makes it more difficult to secure networks once employees are beyond their internet service providers. Firewalls secure the connection between remote employees and your servers.

8 Firewall Best Practices

Harden the firewall and establish a firewall configuration plan

Before deploying a software firewall solution, it is crucial to ascertain that the operating system is not only patched but also hardened. Security teams will also want to be sure their firewalls are configured correctly. The correct configuration also involves configuration at the right time to avoid the risk of introducing security loopholes to their networks as a result of unplanned configurations. This is why a well-defined firewall change management plan is required.

A firewall change management plan has to define the changes that should be made to the firewall configuration and the objectives of the changes. The plan should outline the risks involved as a result of policy changes, their effect on the network, and a mitigation plan to diminish these risks. It should also entail a clear structure of change management exercises between various network teams and accurate audit trails to document the changes made by whom, when, and why.

Also see: 7 Enterprise Networking Challenges 

Map out your firewall deployment

Firewalls are critical to the implementation of zero-trust security in an enterprise. They monitor as well as control access across network boundaries in a traditionally segmented network. This includes instances where the firewall sits in a gateway connecting multiple networks and where it connects isolated devices within a network.

The network interfaces of a firewall get connected to Layer 2 and Layer 3 networks when a firewall is deployed. As a result, these zones can be used to simplify the firewall policy and enable these policies to be customized as needed to provide more granular control.

It is also important to figure out firewall management by determining whether the firewall will require a dedicated management interface. Enterprises should also ensure that serial console access is only accessible via secure and dedicated networks.

Before deploying a firewall, enterprises should also examine whether it stands as a single point of failure and consider deploying at least two in a high-availability cluster to guarantee security in the event of failure of a firewall.

However, to avoid wasting resources by constantly having multiple firewalls active, even when there is a low traffic load, enterprises may identify solutions with a framework that scales with the traffic load. This can prove to be a cost-effective solution, especially in networks with traffic load that experiences seasonal peaks.

Protect the firewall

As a crucial part of the security infrastructure of an enterprise, a firewall needs to be secured from exploitation. There are several approaches an organization can take to ensure their firewalls are protected. They can disable insecure protocols such as telnet and the Simple Network Management Protocol (SNMP). If SNMP has to be used, it has to be under a secure SNMP configuration.

Security and network teams can ensure consistent backups of the configurations and databases are scheduled. They can also allow the auditing of system changes and transmit logs to an external firewall management solution for forensics and reporting.

Implementing a stealth rule in the firewall policy to exclude the firewall from being detected during network scans should also be considered. These teams can also think about limiting access to specific hosts to better the security of their firewalls.

Finally, enterprises can consistently check with firewall vendors for known and emerging vulnerabilities as well as patches, as firewalls are not immune to vulnerabilities.

Routinely audit the firewall

Firewall rules have to be compliant with internal as well as external security regulations applicable to a specific network or the firewalls themselves. Unauthorized changes to firewall configurations can result in policy violations that may render an organization non-compliant. Network and security teams should enforce regular security audits to prevent the consequences of unauthorized changes.

These audits will also provide updates on the necessary changes made and give warnings about the potential risks of changes. Security audits are especially critical when a new firewall has been installed, during firewall migration, and in a scenario where bulk firewall configuration changes are made.

Also see: Best Network Management Solutions 

Block traffic and monitor user access

Security and network teams are advised to block all traffic by default, except for specific traffic to some verified services, to gain total control over who can access their networks and to prevent security incidents.

The privilege to access the firewall and the ability to alter firewall configurations should not be provided carelessly, as the firewall is a crucial layer of protection against threats. Controlling user access is key to making certain only authorized users can access and change firewall configurations.

Furthermore, every time an authorized user alters any configuration, it must be recorded in logs. Aside from audit and compliance purposes, this allows unauthorized configuration changes to be detected and for these changes to be reversed.

Categorizing user profiles according to various levels of access helps to keep track of user access. Users can enjoy access only depending on the tasks they are accorded. Logs need to be monitored constantly to expose any unauthorized access from both outside and inside the network.

Implement a centralized management tool for multi-vendor firewalls

It is common to find enterprises implementing firewalls developed by different companies to increase their security layers, making multi-vendor firewalls quite common. However, these firewalls are often characterized by different architectures, which can complicate their management and effectiveness. When using multi-vendor firewalls, it is important to consider implementing a centralized tool to manage them and make sure they function correctly.

A multi-vendor firewall management tool delivers a unified view of firewall rules and policies to enable enterprises to compare and manage firewall rules without a hassle. Additionally, these tools enable their users to troubleshoot configuration problems and carry out security auditing and troubleshooting.

Also see: Top Enterprise Networking Companies

Update your firewall software

Vendors usually release regular updates and patches for firewall software to address security issues and potential threats by tweaking the software. Firewalls should be constantly updated to ensure your networks are secure and that there are no gaps in the system threat actors can exploit. 

That said, manually keeping track of whether firewalls have been updated may not be the most effective approach. Considering how increasingly opportunistic and devastatingly effective threats continue to be, it may open up enterprises to greater risk of security breaches.

The advancements in technology allow enterprises to avoid lapses in processes such as updating firewalls by making it possible to schedule and automate firewall updates. The reduced human intervention ensures the firewall is constantly secure and robust.

Test to verify the policy and determine risks

It may prove to be a challenge to visualize how a larger security policy processes new connections. IT teams can utilize tools capable of executing path analysis to search and find policy rules.

It is also advisable for them to test their policies to verify they function as intended and find unused and duplicate objects, as it is possible to have duplicate policies and policies containing rules that hide other rules. These teams can also routinely inspect policies and determine the order of rules in the inspection order to optimize the performance of their firewalls.

Collins Ayuya
Collins Ayuya
Collins Ayuya is a contributing writer for Enterprise Networking Planet with over seven years of industry and writing experience. He is currently pursuing his Masters in Computer Science, carrying out academic research in Natural Language Processing. He is a startup founder and writes about startups, innovation, new technology, and developing new products. His work also regularly appears in TechRepublic, ServerWatch, Channel Insider, and Section.io. In his downtime, Collins enjoys doing pencil and graphite art and is also a sportsman and gamer.

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