Firewalls are an important line of defense in computer networks, and properly used can help protect U.S. server systems from unauthorized access, malicious attacks, and cyber threats. Firewalls can be used to monitor, filter, and control network traffic. The following is about how to properly apply the firewall on the server in the United States, I hope to help you!

Understanding Network traffic

Know your network traffic patterns before configuring your firewall. This includes knowing which services and ports are required and which are not. Make sure your firewall rules don't block normal network traffic.

Minimize open ports

Open only the ports required by the system and services, and close the unnecessary ports. Limiting open ports can reduce the surface of a system's exposure to potential attacks.

Default rejection rule

Use the default denial rule to allow only explicitly approved traffic through. Open ports and services only when needed.

Planning rule sequence

Firewall rules are matched one by one in their order until a rule that matches the traffic is found. Therefore, it makes sense to ensure that the order of the rules is meaningful to prevent unnecessary rules from overwriting more specific rules.

Restrict remote access

If possible, limit the range of IP addresses for remote access servers. Only trusted IP addresses are allowed to connect to critical services, such as SSH.

Use strong passwords and keys for authentication

It is highly recommended to use strong passwords and consider using key authentication to increase the security of access to the server. This reduces the risk of a malicious user trying to crack a password.

Review and update the rules regularly

Review the firewall rules regularly to make sure they still meet your needs. If the service or configuration on the server changes, update the firewall rules accordingly.

Monitoring log

Enable firewall logs and monitor them periodically. This helps you spot any potential security issues in a timely manner and take the necessary steps to protect your server.

Using Network Intrusion Detection/Prevention Systems (IDS/IPS)

These systems can help detect and block potential intrusion attempts and enhance server security.

Consider using an application-layer firewall

Application-layer firewalls can detect and block attacks of specific application-layer protocols, improving the defense capability against advanced threats.

Update firewall software in a timely manner

Ensure that firewall software and its rule set are up to date in order to respond to new threats and vulnerabilities in a timely manner.

Educational user

Conduct security awareness training for system users, educate them on how to use secure passwords, avoid clicking on malicious links, etc.

The above recommendations are general firewall best practices, but the actual configuration may vary depending on server usage, network environment, and security needs. Before configuring a firewall, it is best to understand the requirements of your system and applications in order to develop appropriate security policies.