Portal websites are often the focus of distributed denial of service (DDoS) attacks due to their large user scale and concentrated traffic. DDoS attacks initiate massive requests to the target server, consume bandwidth and system resources, and make it inaccessible to normal users. High-defense IP (also known as large-traffic cleaning IP) is a protection product provided by cloud service providers or network security vendors. It sets up large-scale traffic cleaning capabilities on the operator or cleaning node side to identify and discard malicious traffic, thereby ensuring the availability of the source station. When a portal website encounters a DDoS attack, whether the deployment of high-defense IP can completely protect it needs to be evaluated from multiple aspects such as attack type, protection principle, deployment method and supporting strategy.

The core advantage of high-defense IP lies in the large-traffic cleaning capability of the network layer. Cloud security vendors deploy cleaning centers between access links and core backbone networks, and the cleaning capacity can reach tens of Gbps or even Tbps. When traffic anomalies are detected, malicious requests are diverted to the cleaning node, and normal traffic is released after whitelisting or behavior analysis. For traffic attacks, such as UDP flooding, ICMP flooding, DNS amplification, etc., the high-defense IP can intercept most invalid data packets at the operator side in the first time, prevent bandwidth exhaustion and link congestion, and thus ensure the network availability of the portal website. After deploying the high-defense IP, the public network egress traffic of the portal website will be filtered by the cleaning node first, and large-scale traffic protection capabilities can be obtained without deploying additional hardware or software at the source station.

High-defense IP is also effective for protocol exhaustion attacks. SYN flooding, ACK flooding, RST flooding, etc. exhaust the server TCP connection table or CPU resources by constructing a large number of half-connected or forged session packets. High-defense IP enables the SYN Cookie mechanism and session rate limit at the network entrance, identifies and discards connections that have not completed the three-way handshake, and prevents malicious connections from occupying server resources. In addition, through adaptive thresholds and rate control, the protection system can dynamically adjust the number of connections allowed per second, and perform black hole or rate limit processing on abnormal ports and IP segments, thereby reducing the threat of protocol layer attacks to portal websites.

In application layer DDoS attacks, high-defense IP combined with the Web Application Firewall (WAF) module plays a role. Application layer attacks often simulate normal user behavior and exhaust backend CPU or database resources through a large number of legitimate HTTP requests. The WAF integrated with the high-defense IP can perform in-depth detection of fine-grained indicators such as URL access frequency, Header features, and request body signatures. For HTTP Flood attacks, the system can score according to access frequency and source IP, trigger verification code or JS challenge, accurately intercept malicious requests and allow normal users to continue access. For complex OWASP Top10 attacks, such as SQL injection, XSS cross-site scripting or file download abuse, the high-defense IP and WAF linkage post-strategy can quickly intercept and collect attack traffic logs, supporting the security team's subsequent analysis and tracing.

Although the high-defense IP has obvious advantages in large-volume and protocol protection, there are also limitations on deployment and scope of application. First, the high-defense IP needs to cooperate with DNS resolution adjustment to resolve the portal website domain name to the protection IP. If the attacker directly accesses the source station IP or the backup domain name, he can still bypass the cleaning layer to launch an attack, so the source station IP and domain name need to be strictly hidden, and all inbound traffic must go through the protection link. Secondly, the cleaning strategy of high-defense IP is mostly based on traffic characteristics. A very small number of customized or new attacks may not be identified in the early stage, and the security team needs to update the filtering rules and feature library in time. Thirdly, the precise protection of the application layer depends on the perfection of WAF rules. Insufficient configuration of rules and strategies or too high false positives may affect normal business. Therefore, it is necessary to regularly upgrade the blacklist and whitelist and machine learning model to maintain the accuracy of protection.

In order to maximize the protection effect of high-defense IP, the portal website should also take the following supporting measures: deploy minimized services at the source site, open service ports only for real requests from high-defense IP sources to prevent bypass; enable TLS acceleration and certificate verification to avoid performance bottlenecks caused by the encryption layer; combine CDN distribution to cache static content to edge nodes to reduce the bandwidth pressure of the source site; use multi-regional high-defense IP or Anycast acceleration to achieve geographical redundancy of protection nodes to cope with large-scale multi-point distributed attacks. The operation and maintenance team should configure a complete monitoring and alarm system to monitor the cleaning node traffic, attack peaks and system resource usage in real time to ensure early expansion or adjustment of strategies when the traffic approaches the cleaning threshold.

In terms of service provider selection, priority should be given to high-defense IP products with the following characteristics: having a cleaning bandwidth greater than the estimated peak value of the portal website (it is recommended to leave a 50%-100% overflow margin); having multi-node distribution and supporting Anycast or multi-line back to the source; providing real-time monitoring, attack reporting and log analysis interfaces; following the billing model of "pay by protection bandwidth, smart metering" to avoid huge costs due to traffic overflow during the attack; having a mature WAF policy library and security expert team support to quickly respond to new attacks. In addition, the service provider's SLA should clearly define the protection stability, cleaning response time and compensation mechanism to ensure that the portal website can still receive timely response and technical support when encountering large-scale attacks.

Overall, high-defense IP is the core tool for portal websites to deal with various DDoS attacks, and can provide multi-dimensional protection at the network layer, protocol layer and application layer. By deploying and reasonably scheduling high-defense IP, combined with source site isolation, CDN acceleration and WAF rule optimization, portal websites can respond quickly when attacks occur, effectively intercept most malicious traffic, and maintain normal business access. To ensure long-term protection, continuous rule updates, traffic monitoring and security drills must be carried out, high-defense IPs must be incorporated into the overall security strategy, and work together with other security components to achieve comprehensive defense against DDoS attacks.