firewall rules

Configuring firewall rules: what you should know

In today’s hyper-connected digital landscape, safeguarding your valuable data and networks is no longer a mere option but rather an indispensable necessity. Enter the realm of firewall rules – your ultimate line of defence against unauthorised access and malicious cyber threats.

With cyber-attacks evolving at a breakneck pace, our expert guide combines the latest industry insights, practical tips, and best practices to empower you with the skills needed for impenetrable network security.

What are firewall rules?

Firewall rules are essentially a set of instructions that determine how traffic should be allowed or denied within a network. These rules are designed to protect your devices and data from unauthorised access and malicious activities by filtering incoming and outgoing traffic based on predefined criteria.

The default settings of most firewalls are designed to provide a basic level of protection. However, these default settings may not be sufficient to adequately protect your network and its resources. By configuring your firewall rules, you can customise the security settings to suit the specific needs of your network and its users.

Types of firewall rules

Inbound rules: Govern the traffic entering your network from external sources. Inbound rules are essential for protecting your network from unauthorised access attempts and other cyber-attacks.

Outbound rules: Control the traffic leaving your network and heading towards external destinations. Outbound rules can help prevent data exfiltration, where sensitive information is transferred from your network to an external location, usually by a malicious actor. 

Internal rules: Manage the traffic between devices and subnets within your network. Internal rules are crucial for segmenting your network and preventing the lateral movement of threats, which can limit the damage caused by a security breach. 

Application-specific rules: Tailored to specific applications or services running on your network. Application-specific rules can help you maintain granular control over how these applications communicate with the outside world and how they interact with other devices within your network. 

Secure firewall

Before you begin configuring your firewall rules, it is essential to ensure that your firewall is secure. A poorly secured firewall can be vulnerable to attacks, rendering your carefully crafted rules ineffective.

Update your firewall firmware and software: Regularly check for updates to your firewall’s firmware and software, and install them as soon as they become available. Updates often include security patches and enhancements that can help protect your firewall from new threats.

Change default credentials: Many firewalls come with default usernames and passwords. These credentials are well-known to attackers and can be easily exploited to gain unauthorised access to your firewall. 

Create your firewall zones and IP addresses

Firewall zones are logical groupings of network interfaces that share similar security requirements. They can be used to simplify the process of creating and managing firewall rules. By segmenting your network into different zones, you can apply specific rules for each zone that cater to its unique security needs.

When creating your firewall zones, it is essential to carefully plan and document the IP address ranges and subnet masks for each zone. This information will be used when configuring your firewall rules, ensuring that traffic is correctly filtered and routed between zones.

Configure access control lists

Access control lists (ACLs) define the specific criteria that must be met for traffic to be allowed or denied. They can be based on various factors such as IP addresses, protocol types, port numbers, and application signatures.

When configuring ACLs, it is crucial to strike a balance between security and usability. Overly restrictive ACLs can hinder network functionality and cause frustration for users. On the other hand, overly permissive ACLs can expose your network to unnecessary risk. 

Start with a deny-all policy: Begin by creating a policy that denies all traffic by default. This ensures that only traffic explicitly allowed by your ACLs will be permitted to enter or leave your network. 

Create allow rules: After establishing a deny-all policy, create rules that allow necessary traffic based on your network’s requirements. Ensure that you only allow traffic that is essential for the operation of your network and its applications. 

Use the principle of least privilege: When creating allow rules, apply the principle of least privilege. This means that you should only grant the minimum level of access necessary for a device, user, or application to function correctly. 

Regularly review and update ACLs: Periodically review your ACLs to ensure that they remain relevant and effective. Remove any outdated or unnecessary rules and update existing rules as your network requirements change. 

Firewall rules best practices

Following strict best practices will help you configure and manage your firewall rules effectively.

Document rules: Maintain clear and up-to-date documentation of your firewall rules. This can help you troubleshoot issues, identify gaps in your security, and ensure that future changes to your rules are made with a solid understanding of your existing configurations. 

Test rules: Regularly test your firewall rules to ensure that they are working as intended. Use tools like vulnerability scanners and penetration testing to identify weaknesses in your firewall rules.

Implement multi-factor authentication: MFA adds an extra layer of security to your firewall, making it more difficult for attackers to gain unauthorised access. 

Regularly backup firewall configurations: Back up your firewall configurations regularly to ensure that you can quickly restore your firewall in the event of a failure or security breach. 

Configure your firewall rules to your specifications with expert assistance

Firewall rules are an essential component of network security. By mastering the art of firewall rules configuration, you can protect your network from a wide range of cyber threats, prevent data breaches, and optimise network performance.

The cyber security specialists at Steadfast Solutions can customise your firewall rules for your business’s specific needs and fully manage them for maximum effectiveness. Talk to them today and find out more.