DNS is the most fundamental and crucial component, serving as the first hop in all access paths and acting as a "navigation system" between users and servers. Because of this, DNS is highly vulnerable to attackers, most notably DDoS (Distributed Denial of Service) attacks. Many website owners and businesses wonder when building websites or applications: can traditional DNS resolution withstand such attacks? Does it offer any protection? To answer this question, a comprehensive understanding of the principles, bottlenecks, and actual performance of traditional DNS under large-scale attacks is necessary.

　　Traditional DNS was originally designed to provide a mapping between domain names and IP addresses; it wasn't designed for security protection. In the early days of the internet, DNS servers were small, accessed infrequently, and had simple structures, thus requiring no complex security capabilities. However, with the explosive growth in the number of websites and the escalation of cyberattacks, traditional DNS faces increasingly severe challenges, particularly its vulnerability to DDoS attacks. Traditional DNS resolution services rely on fixed nodes with limited resources. Under a massive surge of requests, it is prone to overload, increased latency, and unresolved issues, rendering the website inaccessible and appearing as if the entire site has crashed.

　　When faced with a flood of DNS queries, the biggest problem with traditional DNS is its insufficient "single point of failure." It's typically deployed on a small number of servers with limited bandwidth and low QPS (queries per second) capacity, causing immediate server failure when the attack volume exceeds the server's limits. Since DNS is the entry point for website access, if the DNS goes down, even if the server itself is functioning normally, users cannot access the website. In other words, traditional DNS has almost no proactive defense against DDoS attacks; its behavior is more like "passive absorption," relying entirely on its own ability to handle peak request volumes. With attacks reaching increasingly larger scales, often tens or even hundreds of Gbps, the protection capability of traditional DNS is virtually zero.

　　On the other hand, the deployment method of traditional DNS also limits its defensive capabilities. It often uses a single machine or a small number of nodes. For small and medium-sized enterprises, self-built DNS typically consists of only one or two DNS servers. This architecture is extremely vulnerable to precise attacks. Attackers don't need complex strategies; simply continuously launching a large number of query requests to the DNS can overwhelm it. Moreover, even with high-performance hardware, self-built DNS cannot solve the problems of limited bandwidth and the limited number of nodes; the network egress point itself determines the maximum carrying capacity. In such situations, DDoS attacks can easily overwhelm traditional DNS, causing complete business shutdowns.

　　Besides query-based attacks, DNS itself can act as an attack amplifier, such as in DNS amplification attacks. Attackers send extremely small requests with forged source addresses, yet trigger server responses tens of times higher, causing widespread disruption across the internet. Traditional DNS cannot identify the source of malicious requests and lacks filtering capabilities, simply responding according to standard protocols, further amplifying the attack threat. For sites using traditional DNS, even if not directly attacked, they may be affected by such attacks, leading to network congestion, resolution failures, and abnormal access.

　　From a security perspective, traditional DNS also lacks defensive capabilities. For example, it cannot identify abnormal source IPs based on intelligent policies, allowing it to accept an unlimited number of resolution requests from anywhere, nor can it perform rate limiting or intelligent origin-based routing. Once network-wide traffic floods a single node, network and server resources are instantly exhausted. Large DNS service providers possess strong protection capabilities due to technologies such as global multi-node Anycast networks, automatic redirection, link redundancy, and filtering rules; these are capabilities that traditional DNS lacks, resulting in a significant difference in their attack resistance levels.

　　However, while traditional DNS itself cannot defend against DDoS attacks, it is not entirely useless. For small sites or websites with low traffic, traditional DNS can still operate stably if the target is not obvious. But as soon as the business reaches a certain scale, targets a global user base, or faces intense competition, the probability of being attacked increases significantly, at which point the weaknesses of traditional DNS become apparent. If website owners continue to rely on traditional DNS, not only will their websites be more vulnerable to attacks, but it may also cause long-term damage to their brand and user experience.

　　To improve their DNS-level protection capabilities, many enterprises are migrating to "cloud DNS" or "high-defense DNS" platforms. These services possess global multi-node, clustered architecture, Anycast acceleration, intelligent scheduling, request filtering, QPS protection, and DDoS redirection and cleaning capabilities, easily withstanding attack traffic that ordinary hackers cannot handle. Unlike traditional single-point DNS deployments, cloud DNS relies on a globally distributed network, distributing attack traffic across numerous nodes and significantly improving resilience. For example, when an attack reaches hundreds of thousands of QPS, cloud DNS can maintain stable resolution, while traditional DNS might completely collapse within seconds.

　　Furthermore, high-defense DNS includes more advanced features such as intelligent routing, cross-regional disaster recovery, cache eviction, protocol optimization, traffic analysis, and blacklist control. This makes DNS not only a basic resolution tool but also an integral part of a website security and access acceleration system. Therefore, traditional DNS cannot compare to modern high-defense DNS, especially when facing DDoS attacks; the difference is enormous.

　　Enterprises must consider their own business characteristics when choosing a DNS protection solution. If a website has high traffic, global access, or involves finance, e-commerce, login systems, or API services, it should not continue to rely on traditional DNS, as breaching the entry point is extremely costly for attackers, while the protection value is enormous. Conversely, if it's just a personal blog or a small showcase site not exposed to high-risk industries, traditional DNS can meet daily needs. However, once a business reaches a certain scale, upgrading to a DNS service with enhanced protection becomes inevitable, just as a website must upgrade from shared hosting to a dedicated server.

　　In summary, traditional DNS is essentially defenseless against modern DDoS attacks and lacks proactive protection mechanisms. Once attacked, the resolution service almost inevitably ceases, and the website crashes. To defend against DDoS attacks, it's essential to rely on specialized cloud-based DNS or high-defense DNS technologies, which utilize distributed nodes, Anycast acceleration, and intelligent filtering to achieve strong attack resistance. DNS is the gateway to a website, and once that gateway is breached, no amount of server configuration will help. Therefore, understanding the limitations of traditional DNS is a crucial step in building a stable website. Choosing a DNS service with higher protection capabilities is an essential foundation for modern internet businesses.