What should I do if DNS is contaminated? Teach you quick troubleshooting and solutions

in the process of daily Internet access, many people will encounter the situation that the network connection is normal, but they cannot access a specific website, or the webpage jumps to an unfamiliar malicious page, which is likely to encounter DNS pollution. This network problem will interfere with the normal domain name resolution process, which not only affects the Internet experience, but also may bring information security risks. This article will start from the whole process of investigation, solution to protection, and dismantle the DNS contaminated response plan for everyone, so that you can quickly return to the normal network environment.

, how to determine whether the DNS is contaminated?

to solve the problem, we must first accurately locate and determine whether DNS is contaminated. We need to combine several typical symptoms and test methods to avoid confusion with ordinary network failures.

1, observe network abnormal symptoms

The most typical manifestation of

DNS pollution is that specific websites cannot be accessed, such as overseas regular websites or some technical sites, while most domestic websites can be opened normally; in addition, web pages may jump to unfamiliar advertising pages, domain name resolution timeout, and different devices under the same network. The same abnormality occurs, which may be a signal that DNS is polluted.

2. Test

with command line tools

can use the ping and nslookup commands for testing, enter the ping instruction of the corresponding domain name in the computer command prompt, if the returned Internet Protocol Address obviously does not conform to the IP officially announced by the website, or the resolution results of the nslookup query are chaotic and changeable, it can be determined that the DNS is polluted.

What are the basic solutions to DNS pollution?

confirm that DNS is contaminated, you can try the basic solution first, this kind of operation is simple and easy to use, in most cases can quickly alleviate the problem.

1 Replacing public DNS servers

the default operator DNS server is a common target of DNS pollution, replace it with domestic or international public DNS to avoid pollution. For example, domestic 114.114.114.114, Ali's 223.5.5.5, international 8.8.8.8, etc., find the DNS server address option in the network settings, manually enter the new address and save it to take effect.

2, refresh the local DNS cache

DNS contaminated, the local device may have cached the wrong resolution results, and even if the DNS is changed, it cannot be restored immediately. At this time, you can enter the ipconfig /flushdns command at the command prompt to empty the local DNS cache and let the device re-initiate the resolution request to the new DNS server. In most cases, normal access can be quickly restored.

What is the advanced repair plan for DNS pollution?

if the basic method cannot solve the DNS pollution problem, it may be that the pollution is deep and needs to be repaired from the resolution link level by means of advanced means.

1, use encrypted DNS protocol

ordinary DNS protocol uses plaintext transmission, which is easy to be intercepted and tampered with to cause DNS to be polluted. Encrypted DNS protocols such as DoH or DoT can encrypt the transmission of resolution requests to avoid being tampered in the middle. At present, mainstream browsers and some routers support turning on the encrypted DNS function. Just select the corresponding encrypted DNS server address in the settings to enable it.

2, modify the local hosts file

For specific websites contaminated by DNS, you can manually modify the local hosts file, directly bind the website domain name to the correct Internet Protocol Address officially announced, and bypass the DNS resolution process. When operating, you need to find the hosts file under the system disk, open it with Notepad and add the mapping relationship between the corresponding domain name and IP. After saving, you can directly access the target website through IP.

How to avoid DNS contamination again?

solve the current DNS pollution problem, doing a good job of daily protection can reduce the probability of being caught again and maintain a long-term stable network environment.

1, long-term use of reliable DNS servers

do not switch to unknown small service providers DNS, long-term fixed use of verified public encrypted DNS server, such servers usually have a more perfect anti-pollution mechanism, can effectively reduce the risk of DNS contamination, while ensuring the resolution speed and stability.

2, regularly check the network resolution status

develop the habit of regularly checking the DNS resolution status, monthly use nslookup tool to randomly check the resolution results of several commonly used websites, if any abnormalities are found, timely troubleshooting and processing; while maintaining the firmware update of routers and equipment systems, many updates will fix cyber security vulnerabilities, reduce DNS pollution opportunities.

To sum up, DNS pollution is a common network interference problem. From accurate judgment to basic solution, to advanced repair and daily protection, a complete set of coping processes can be efficiently handled. You can try from a simple method according to the specific situation of your own network abnormality, and gradually investigate and solve it. At the same time, long-term protection can effectively avoid the network troubles caused by DNS pollution, and ensure the smooth and safe Internet access.