DNS pollution refers to adding false information to the DNS server during the DNS analysis process to interfere with the normal domain name analysis, resulting in the user being redirected to the wrong website or service. DNS pollution may be for malicious purpose, or it may occur due to configuration errors or failures. The following is the cause and solution of DNS pollution:

　　reason:

　　Malicious attacks: Hackers or malicious molecules may try to implement DNS pollution by adding false DNS records to DNS servers to guide users to malicious sites.

　　Configuration error: In some cases, the configuration error of the DNS server may cause pollution. This may be caused by an administrator's wrong configuration or unsafe settings.

　　DNS cache problem: Some intermediate devices (such as local DNS cache or ISP DNS server) may cache false DNS records, resulting in DNS pollution.

　　Solution:

　　Use trustworthy DNS server: DNS servers provided by trusted organizations or services, such as Google DNS or OpenDNS. These DNS servers are usually better maintained and monitored, and they are even more uncomfortable to be affected by DNS pollution.

　　DNSSEC: DNSSEC (DNS security extension) is a protocol for protecting the DNS parsing process from pollution. Enabling DNSSEC to verify the authenticity of the DNS record to ensure that what you get is the correct analysis result.

　　Regular monitoring and review DNS configuration: If you are a network administrator, check the configuration of the DNS server regularly to ensure that there are no configuration errors. Monitor the logs of the DNS server and the activity of domain name analysis, and find problems in time.

　　Clear DNS cache: If you suspect the DNS cache problem, you can try to remove the DNS cache on the local computer or router. The use command is as follows:

　　For Windows:

　　Ipconfig /Flushdns

　　For linux:

　　SUDO SYSTEMCTL RESTART SYSTEMD-Resolved

　　For routers, please check the document of the router to understand how to clear the DNS cache.

　　Cyber security strategy: Implement effective network security strategies, including firewalls, invasion detection systems and security audits to detect and prevent malicious DNS attacks.

　　Report Question: If DNS pollution is suspected, you can report the problem to your ISP or DNS service provider so that they can take measures to solve the problem.

　　In short, DNS pollution is an important issue of security and network stability. By adopting preventive measures and appropriate solutions, you can reduce the risk of being attacked by DNS pollution. If you suspect that you are attacked by DNS pollution, it is recommended to take measures as soon as possible to solve the problem.