When employees repeatedly report that "the website is inaccessible" while the network connection appears normal, the problem is likely DNS poisoning. This situation is quietly eroding operational efficiency, and many companies only realize its existence when business is affected.

Detecting DNS poisoning is not a complex technology; any company can proactively identify and resolve the issue through a systematic approach. The most direct starting point is a basic check of the internal network. Opening the command prompt and executing the `nslookup` command on frequently used domains is a quick initial check. When the same domain returns a clearly incorrect IP address—for example, resolving a well-known website to a completely unrelated address, or frequently pointing to a local loopback address like 127.0.0.1—the likelihood of poisoning is quite high. Further analysis using the `dig` command and examining the authority indicators of the responses provides more detailed information.

Relying on a single detection point is far from sufficient. Savvy companies establish a multi-point detection matrix, simultaneously initiating queries from the internal network, cloud servers, different ISP lines, and even overseas nodes. Cross-referencing the internal DNS resolution results with the data from these external nodes will reveal anomalies. Especially when the IP addresses returned by overseas nodes differ significantly from those of domestic nodes, and this difference points to clearly incorrect addresses, DNS poisoning is almost certain. This method not only verifies initial suspicions but also helps pinpoint the scope and nature of the poisoning.

Of course, enterprises can also leverage readily available detection tools to improve efficiency. Many network security vendors offer online DNS poisoning detection services; simply enter the domain name, and the system will initiate queries from multiple nodes globally and generate analysis reports. For enterprises with strong technical capabilities, deploying professional monitoring software is a more sustainable and effective solution. These systems can continuously track the resolution status of critical domain names and immediately alert upon detecting anomalies.

At a deeper analysis level, enterprises need to focus on several key indicators. Abnormal fluctuations in TTL values ​​often indicate a problem—when the TTL of a query result is abnormally regular or remains constant, it may be a characteristic of poisoning. Equally important is verifying the authenticity of the returned IP addresses. By reverse-checking the ASN (Autonomous System Number) to which the IP belongs, if it is found that the IP does not belong to the target company's ASN, or even a non-existent ASN, the likelihood of poisoning is extremely high.

For enterprises with their own domain names, monitoring the resolution status of their own domains is equally crucial. Regularly checking your domain names for incorrect IP addresses, especially testing under different network environments, can help detect DNS attacks targeting your organization promptly.

Institutionalizing this detection process is core to enterprise-level response. Have your IT team conduct monthly systematic checks on core business domains, establishing a baseline database of DNS queries and recording normal resolution patterns for critical domains. When employees widely report unusually slow or inaccessible websites, initiate an emergency detection process. Simultaneously, deploy HTTP When employees repeatedly report that "the website is inaccessible" while the network connection appears normal, the problem is likely DNS poisoning. This situation is quietly eroding operational efficiency, and many companies only realize its existence when business is affected.

Detecting DNS poisoning is not a complex technology; any company can proactively identify and resolve the issue through a systematic approach. The most direct starting point is a basic check of the internal network. Opening the command prompt and executing the `nslookup` command on frequently used domains is a quick initial check. When the same domain returns a clearly incorrect IP address—for example, resolving a well-known website to a completely unrelated address, or frequently pointing to a local loopback address like 127.0.0.1—the likelihood of poisoning is quite high. Further analysis using the `dig` command and examining the authority indicators of the responses provides more detailed information.

Relying on a single detection point is far from sufficient. Savvy companies establish a multi-point detection matrix, simultaneously initiating queries from the internal network, cloud servers, different ISP lines, and even overseas nodes. Cross-referencing the internal DNS resolution results with the data from these external nodes will reveal anomalies. Especially when the IP addresses returned by overseas nodes differ significantly from those of domestic nodes, and this difference points to clearly incorrect addresses, DNS poisoning is almost certain. This method not only verifies initial suspicions but also helps pinpoint the scope and nature of the poisoning.

Of course, enterprises can also leverage readily available detection tools to improve efficiency. Many network security vendors offer online DNS poisoning detection services; simply enter the domain name, and the system will initiate queries from multiple nodes globally and generate analysis reports. For enterprises with strong technical capabilities, deploying professional monitoring software is a more sustainable and effective solution. These systems can continuously track the resolution status of critical domain names and immediately alert upon detecting anomalies.

At a deeper analysis level, enterprises need to focus on several key indicators. Abnormal fluctuations in TTL values ​​often indicate a problem—when the TTL of a query result is abnormally regular or remains constant, it may be a characteristic of poisoning. Equally important is verifying the authenticity of the returned IP addresses. By reverse-checking the ASN (Autonomous System Number) to which the IP belongs, if it is found that the IP does not belong to the target company's ASN, or even a non-existent ASN, the likelihood of poisoning is extremely high.

For enterprises with their own domain names, monitoring the resolution status of their own domains is equally crucial. Regularly checking your domain names for incorrect IP addresses, especially testing under different network environments, can help detect DNS attacks targeting your organization promptly.

Institutionalizing this detection process is core to enterprise-level response. Have your IT team conduct monthly systematic checks on core business domains, establishing a baseline database of DNS queries and recording normal resolution patterns for critical domains. When employees widely report unusually slow or inaccessible websites, initiate an emergency detection process. Simultaneously, deploy HTTP access checks, rather than simple DNS query checks, for critical business applications, as some advanced poisoning methods may only be effective at the HTTP level.

The ultimate goal of detection is not only to identify problems but also to provide a basis for subsequent mitigation measures. When DNS poisoning is confirmed, enterprises can consider deploying encrypted DNS protocols such as DoH or DoT, switching to a more reliable DNS resolution service, or establishing a trusted query channel via 私人专属网络.

DNS poisoning detection should not be considered a one-off task but a routine component of daily enterprise network security operations. By establishing a systematic detection mechanism, enterprises can detect and take action early on before this seemingly invisible threat impacts core business operations, ensuring a healthy and stable network environment.

access checks, rather than simple DNS query checks, for critical business applications, as some advanced poisoning methods may only be effective at the HTTP level.

The ultimate goal of detection is not only to identify problems but also to provide a basis for subsequent mitigation measures. When DNS poisoning is confirmed, enterprises can consider deploying encrypted DNS protocols such as DoH or DoT, switching to a more reliable DNS resolution service, or establishing a trusted query channel via 私人专属网络.

DNS poisoning detection should not be considered a one-off task but a routine component of daily enterprise network security operations. By establishing a systematic detection mechanism, enterprises can detect and take action early on before this seemingly invisible threat impacts core business operations, ensuring a healthy and stable network environment.