Many users using Hong Kong servers have discovered that despite low website traffic, the servers frequently experience abnormal CPU usage, network congestion, or even outright downtime. The most common threats are DDoS attacks and malicious intrusions. Deploying a proper firewall and DDoS protection is a fundamental and crucial step to ensuring long-term stable server operation in such a network environment.

　　The core of server security lies in "prevention" and "control." "Prevention" prevents attackers from gaining access to the system or causing resource depletion, while "control" ensures that even if an attack occurs, damage is limited and recovery is rapid. A Hong Kong server's protection system typically addresses two key areas: network-layer firewall rules and access control, and DDoS defense strategies against high-volume attacks.

　　A firewall is the server's first line of defense. It acts like a door, allowing only requests that meet the required rules to enter and rejecting abnormal, malicious, or unnecessary connections. Common firewalls include software and hardware. Software firewalls are typically deployed at the operating system level, such as Linux's iptables, firewalld, and UFW, and Windows Server's built-in security policies. Hardware firewalls, located at the network perimeter and provided by the computer room or network equipment, filter traffic in real time.

　　In a Hong Kong server environment, properly configuring a firewall can effectively reduce the risk of intrusion. For example, many hackers scan common ports (such as 22, 3306, and 3389) for vulnerable targets. If users don't modify default ports or set access restrictions, attackers can easily attempt brute-force attacks. Therefore, the first step is to close unnecessary ports and only keep those required for business operations. For example, a web server typically only needs to open ports 80 and 443, disabling all others. For remote management ports like SSH or RDP, whitelisting can be used to restrict access to specific IP addresses, or using non-default ports can reduce the risk of being scanned.

　　Furthermore, firewalls can prevent hackers from conducting password guessing attacks through connection limits, anti-brute-force cracking rules, and log monitoring. For example, iptables can configure a maximum number of connections allowed per minute, automatically banning IP addresses if the limit is exceeded. UFW can be combined with fail2ban to dynamically block hosts with excessive login failures. While simple, these strategies are effective in preventing common attacks.

　　A higher-level security strategy is "layered defense." Many companies build a multi-layered defense structure on their Hong Kong servers, such as using a cloud firewall or CDN for DDoS protection on the outer layer, a data center firewall in the middle layer, and system-level rules within the inner layer. This way, even if one layer is breached, the other layers can continue to intercept the attack, preventing a complete loss of security.

　　However, firewalls primarily protect against "small-volume attacks" and "intrusions" and are often insufficient against large-scale DDoS attacks. DDoS (Distributed Denial of Service) attacks involve a large number of zombie servers or control nodes sending invalid requests to the target server, rapidly depleting bandwidth and system resources, rendering the server unable to respond to normal user requests. This type of attack is particularly common on Hong Kong servers exposed to the public internet. Because Hong Kong nodes offer low latency and high bandwidth, attackers often choose them as a testing ground.

　　The key to DDoS defense lies in "identification" and "traffic diversion." Traditional firewalls cannot withstand traffic attacks of tens or even hundreds of Gbps, necessitating the intervention of specialized DDoS protection systems. This type of system is typically deployed at network edge nodes. Through traffic cleaning, signature recognition, and distributed forwarding, it filters out anomalous traffic, retaining only genuine requests and forwarding them back to the origin server.

　　Common DDoS protection methods in Hong Kong data centers include high-defense IP, CDN protection, and cloud scrubbing services. High-defense IP is the most straightforward solution. The service provider hides your server IP behind a protection node, and all access traffic is first filtered by the scrubbing system. When a DDoS attack is detected, the protection system automatically discards invalid packets and only forwards genuine access requests. This not only ensures website availability but also prevents the attack from spreading to other services.

　　For website-based services, CDN traffic distribution can also be combined with CDN. CDN nodes cache website content globally. When attack traffic is concentrated on a single node, the system automatically diverts traffic to other nodes, reducing the pressure on the origin server. Real-time-critical services such as game servers and live streaming systems can also utilize Hong Kong's high-defense lines, using hardware protection devices for real-time traffic filtering.

　　However, DDoS protection isn't as simple as simply purchasing a high-defense IP. Different types of attacks require different strategies. For example, SYN flood attacks exploit TCP handshake vulnerabilities to send a large number of half-connected requests, exhausting server resources; UDP floods saturate bandwidth by sending a large number of forged packets; and HTTP floods disguise themselves as genuine user requests, causing application crashes. To address these situations, enterprises should implement a layered defense strategy: using high-defense nodes to filter traffic at the network layer, limiting concurrent connections at the system layer, and using WAFs (Web Application Firewalls) at the application layer to identify abnormal requests.

　　WAFs can detect malicious access patterns, such as SQL injection, cross-site scripting, and CC attacks, preventing attackers from exploiting vulnerabilities to compromise websites. For website systems running on Hong Kong servers, especially those in e-commerce, finance, and gaming backends, WAFs are an essential security layer. They learn normal traffic behavior and automatically adjust rules to address evolving attack vectors.

　　In addition to deploying protective measures, security strategies should also include routine maintenance and monitoring. Server security isn't a "set it once and for all" approach; it's an ongoing process. Regularly updating system patches, upgrading application versions, disabling unused services, and restricting root remote logins are all fundamental security practices. At the same time, configure a log auditing system to record all access and operation behavior, allowing for quick source identification in the event of anomalies. For high-value businesses, use a security monitoring platform to track changes in connection counts in real time, triggering alerts immediately if traffic anomalies occur.

　　In the actual use of Hong Kong servers, many users neglect security measures, leading to website hijacking, database theft, and even complete server takeover by hackers. Servers using default passwords and without firewalls are particularly vulnerable targets. Firewalls and DDoS protection not only defend against attacks but also serve as the foundation for maintaining business reputation and customer trust.

　　Of course, security must be balanced with performance. Overly restrictive firewall rules can hinder normal access. For example, restricting too many IP addresses or enabling complex authentication mechanisms can degrade user experience. Therefore, protection strategies should be flexibly tailored to the business type. For general corporate websites, enabling basic firewall rules, restricting login IP addresses, and using a CDN are sufficient. However, for gaming or financial services, high-security lines, real-time traffic monitoring, and automatic switching mechanisms are required.