A firewall for optimal protection is a crucial component of network security since it is the first line of protection against internet attackers. Although firewall configuration might be a daunting operation, simplifying it substantially is done by breaking it down into more straightforward phases. The phases that follow outline the primary firewall configuration steps.
A variety of firewall configurations are available for network protection. Discuss your alternatives with a PCI security specialist or a HIPAA security expert to learn more. The following procedures are required regardless of the type of firewall selected. This lesson requires the usage of an enterprise-class firewall that supports numerous internal networks (or zones) and stateful packet inspection.
Due to the technical nature of firewalls, a step-by-step guide is beyond the scope of this blog post. I will give you some hints to help you visualize the process and learn how to configure a firewall in 5 steps.
Getting to Know Firewall
A firewall is a network security device that monitors incoming and outgoing network traffic and permits or blocks data packets according to a set of security rules. It creates a physical barrier between your internal network and incoming traffic (such as the internet), blocking hackers and viruses.
How Does a Firewall Work?
Firewalls thoroughly check incoming communication against established criteria and filter traffic from untrusted or questionable sources to avoid attacks. Firewalls monitor traffic at the ports of a computer, which are the entrance points for data to be shared with external devices. For instance, “Source address 172.18.1.1 is permitted to reach destination 172.18.2.1 over port 22.”
Think about port numbers as rooms and IP addresses as homes. It is further filtered so that only the owner, a child, or a guest can access particular rooms (destination ports) within the house. Only trusted individuals (source addresses) may enter the residence (destination address). Children and guests are restricted to a small number of rooms, whereas the owner has access to every room (port) (specific ports).
Types of Firewalls
Firewalls can be software- or hardware-based; however, having both is optimal. A physical firewall is a piece of hardware between your network and the gateway. In contrast, a software firewall is a program that restricts traffic via port numbers and programs and is installed on each computer.
The most prevalent sort of firewalls, packet-filtering firewalls, examine packets and block them from passing if they do not adhere to a set of security rules. This firewall verifies the packet’s source and destination IP addresses. If packets match to allow the parameters of a firewall’s rule, permit them to enter the network.
Stateful and stateless packet-filtering firewalls are the two subgroups. Because stateless firewalls lack context and examine each packet independently, they are vulnerable to attack. On the other hand, stateful firewalls are believed to be significantly more secure because they keep track of previously passed packet data.
Although packet-filtering firewalls can be successful, they provide only the most fundamental protection and are frequently reasonably limited. For instance, they cannot determine whether the request’s contents would negatively affect the application to which they are replying. The firewall would be unaware if, for instance, a malicious request from a trusted source address resulted in the deletion of a database. Proxy and firewalls of the future generation are better able to detect such attempts.
Next-Generation Firewalls (NGFW)
Integrate anti-virus, encrypted traffic inspection, and intrusion prevention technologies with standard firewall technology. Deep packet inspection is the most noteworthy aspect (DPI). Deep packet inspection examines the data included within the packet itself, whereas typical firewalls examine packet headers. It enables users to identify, classify, or block packets carrying harmful data more precisely. This page contains additional details about Forcepoint NGFW.
Proxy Firewalls for Optimal Protection
Filtering of application-specific network packets In contrast to basic firewalls, the proxy functions as an intermediary between two end systems. A client request must pass via the firewall, Authitizing it or rejecting it based on a set of security criteria. Mainly, proxy firewalls employ stateful and deep packet inspection to detect malicious traffic for layer seven protocols such as HTTP and FTP.
Network Address Translation (NAT) Firewalls
Permit numerous devices to connect to the internet using a single IP address but concealing the IP addresses on each device. As a result, attackers searching for network IP addresses cannot gather exact information, enhancing the security against attacks. NAT firewalls, like proxy firewalls, function as intermediaries between a computer network and external traffic.
Stateful Multilayer Inspection (SMLI) Firewalls
Filter packets at the network, transport, and application levels by comparing them to packets that are known to be trustworthy. SMLI firewalls, like NGFW firewalls, evaluate the entire packet and only permit it to pass if each layer is traversed independently. These firewalls check packets to assess communication status (thus the name), ensuring that any initiated contact only occurs with trustworthy sources.
How to Configure Your Firewall for Optimal Protection
Configure the Firewall Properly
The provider often hardens operating systems for all-inclusive firewall solutions. Patch the operating system and hardened it before adopting a software firewall solution.
In addition to beginning with a hardened operating system, security administrators must configure it to ensure the firewall is correctly. The Center for Internet Security (CIS), which produces the CIS Benchmarks Network Devices, is among the companies and independent groups that publish guides. Check out the SANS Firewall Checklist as well.
Plan the Deployment of Your Firewall
Firewalls are crucial for adopting zero-trust security principles. In a micro-segmented network, they monitor and manage inbound and outbound access across network borders. It applies to layer two bridge and layer three routed firewall deployments (where the firewall connects various networks) (where the firewall connects and isolates devices within a single network).
During firewall implementation, connect these networks or zones to the firewall’s network interfaces. The use of these zones can then simplify the firewall policy. A perimeter firewall, for instance, may contain:
- A DMZ network connection.
- Connect one or more internal interfaces to internal networks.
- An outside zone connected to the internet.
Modify the firewall policy as necessary to provide more accurate control.
Administration of the firewall will be necessary. Will the firewall additionally require a management interface? It is a vital question. Access to serial consoles and lights-out confine management should only secure networks.
In conclusion, a single firewall is a single point of failure (SPOF). When employing two or more High Availability (HA) clusters, even if one fails, maintain security. A hyperscale network security solution is preferable because it continuously uses each cluster member’s resources. Additionally, networks that undergo seasonal traffic peaks should take this into account.
Fully Control the Firewall
Protecting a firewall from exploitation as part of a company’s security infrastructure. To safeguard your firewall, follow these steps:
- Instead, use a secure SNMP setup or disable insecure protocols such as telnet and SNMP.
- Configure frequent database and configuration backups.
- Enable system change auditing and use secure Syslog to transport logs to a firewall management application or external, secure, central SIEM server for forensic analysis and reporting.
- Include a stealth rule in the firewall policy to prevent network scans from detecting the firewall.
- limiting administration access to particular hosts
- Not even firewalls are immune to problems. Inquire with the vendor about any available security upgrades that address known vulnerabilities.
Lockdown Traffic Access
A firewall’s principal purpose is to control and enforce network segmentation access.
Firewalls can inspect and govern north-south traffic flowing across a network boundary. The zones in this macro segmentation application include the outside, internal, DMZ, and guest Wi-Fi networks. They could also be business units with many internal networks, such as a data center, HR department, and finance department, or a factory production floor with industrial control systems (ICS).
Firewalls implemented in virtualized private or public clouds can inspect dynamically changing traffic between individual servers or applications. In this example of micro-segmentation, create the zones by web applications or databases. Suppose the function of setting the virtual server by a tag and used dynamically in a firewall policy without human interaction. In that case, manual configuration problems are less likely to occur.
Firewalls Control Access
in macro and micro deployments by developing a firewall policy rule that generally defines access depending on the source and destination of the traffic. Additionally, it is possible to specify the service and port used by the program. For example, the default ports for web traffic are 80 and 443. Only these ports should be accessible on a web server; block all others. In this circumstance, it is feasible to allow authorized traffic.
Allow listing security policies to struggling with egress traffic from an organization to the internet since it is practically impossible to determine which ports are necessary for Internet access. A more prevalent way for an egress security policy is blocklisting, which is known for prohibeting malicious traffic. In contrast, all prohibit other traffic by a “accept all” firewall policy rule.
The next-generation firewall (NGFW) setting to identify known harmful websites in addition to IP and port limitations. Controlling programs and screening URLs are two examples. Use It, for instance, to enable Facebook while restricting Facebook game access.
Check Policy and Risks
It can be challenging to envisage how a more extensive security policy would handle a new connection. There are tools for path analysis, and the security management system may contain tools for rule searching.
In addition, some security management systems generate a duplicate object alert or refuse to install a policy that conceals another rule. Regularly test your policy to verify that it detects unused and duplicated items.
Moving top hit criteria higher in the inspection sequence can enhance the efficacy of firewall policies, apply generally from the top down. Regularly reviewing the policy will improve the performance of your firewall.
Conduct frequent penetration testing to identify threats and assess if further security measures beyond requiring the firewall to protect your organization.
Final Words
Once your firewall is in production, the configuration is complete, but firewall administration has just begun. Renew firewall rules, logs, firmware, and vulnerability checks every six months. To guarantee that your firewall continues to secure your network, you must document your procedure and be vigilant in carrying out these ongoing responsibilities.
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