Configuring a firewall involves several steps to ensure its proper setup and functionality, from initial securing to testing. Here are the steps typically involved in the firewall configuration process.
Securing a firewall ensures that only authorized administrators can access it. This involves several elements:
Keeping the firewall updated with the latest firmware.
Implementing appropriate configurations before deploying firewalls into production.
Disabling default accounts and changing default passwords to prevent unauthorized access attempts.
Using strong passwords to enhance the security of administrator accounts.
Avoiding the use of shared user accounts. In cases where multiple administrators manage a firewall, it is crucial to establish additional admin accounts with restricted privileges based on individual responsibilities.
Simple Network Management Protocol (SNMP), which gathers and organizes information about devices on IP networks, should be either deactivated or set up to prevent potential security breaches.
Enforcing outgoing and incoming network traffic restrictions for targeted applications. This helps control and regulate the data flow, reducing the risk of unauthorized access or data breaches.
To protect network assets and resources, it is essential to identify them and establish a structured approach. This involves grouping corporate assets into zones based on their functions and the level of risk they pose.
An excellent illustration of this practice is segregating servers, such as email, VPN, and web servers, into a dedicated demilitarized zone (DMZ). The DMZ limits inbound internet traffic, bolstering security measures. Creating multiple zones within the network enhances network security, allowing for better traffic control and management.
Once a network zone structure is established, aligning it with an appropriate IP address structure is crucial. This ensures that zones are correctly assigned to firewall interfaces and subinterfaces, enabling effective traffic monitoring and control.
ACLs play a vital role in network security by enabling organizations to regulate traffic flow between zones. ACLs should be configured with precision, specifying source and destination port numbers and IP addresses. Implementing a “deny all” rule at the end of each ACL ensures that unauthorized traffic is filtered out.
Furthermore, each interface and subinterface should have inbound and outbound ACLs to authorize only approved traffic. To safeguard configuration and prevent unauthorized access, it is recommended to restrict public access to firewall administration interfaces and turn off
unencrypted firewall management protocols.
Firewalls can be configured to accommodate additional services, including:
Dynamic Host Configuration Protocol (DHCP): A network server that automatically assigns and manages IP addresses to a network device, allowing them to communicate and access network resources.
Intrusion Prevention System (IPS): A security technology that monitors network traffic for malicious activities and takes preventive actions to block or mitigate potential threats, such as malware or network-based attacks.
Network Time Protocol (NTP) server: A network server that synchronizes the time across devices and systems in a network, ensuring accurate timekeeping and coordination.
Conduct thorough testing to verify that the firewall functions as intended. Testing helps identify any vulnerabilities or misconfigurations that may expose your system to potential threats.
The firewall setup testing can include things like network segmentation controls, rule verification, and logging and monitoring review.
When setting up a firewall, there are several important factors to watch out for to ensure adequate network security, including your firewall type, logging and monitoring systems, and implementing a disaster recovery plan.
Choose the appropriate type of firewall based on your network requirements. Common types include packet-filtering firewalls, stateful inspection firewalls, and proxies with advanced features like intrusion detection and prevention.