How can individual users regain control of their internet navigation when faced with DNS pollution? DNS translates familiar domain names into IP addresses. However, the DNS protocol lacked security verification mechanisms when originally designed, making man-in-the-middle attacks possible. Attackers tamper with DNS responses, redirecting users to malicious servers to steal sensitive information or commit fraud. According to statistics, approximately 18% of internet users worldwide will have experienced DNS pollution to varying degrees by 2025. Mastering the following protective measures will become essential for safe surfing.

The most direct and effective solution: Enable encrypted DNS services.

Encrypted DNS is currently one of the most effective technologies to combat DNS pollution. Traditional DNS queries are transmitted in plain text, like a postcard sent without an envelope. Their contents can be viewed and tampered with at any point along the way. Encrypted DNS, on the other hand, encrypts communications using the HTTPS or TLS protocols, ensuring the privacy and integrity of the query process.

Two mainstream standards exist for this implementation: DNS over HTTPS (DoH) and DNS over TLS (DoT). DoH encapsulates DNS queries within the HTTPS protocol, making them indistinguishable from regular web browsing traffic and difficult to identify and interfere with. DoT, on the other hand, establishes a TLS-encrypted channel specifically for DNS communications, providing end-to-end protection. Major browsers such as Chrome, Firefox, and Edge already have built-in support for encrypted DNS. Users simply search for "Secure DNS" or a similar option in their settings, enable it, and choose a public encrypted DNS service provided by providers like Google.

Mobile devices also support encrypted DNS. Android users can configure private DNS in their network settings, while iOS users can gain protection by installing specific configuration profiles or using apps that support encrypted DNS. Encrypted DNS not only protects against spam but also prevents ISPs from collecting browsing history, enhancing online privacy.

A Basic and Reliable Solution: Modifying the System DNS Server

If configuring encrypted DNS is too technical for you, modifying the system's default DNS server is a simpler and more direct alternative. Most ISP-operated DNS servers offer mediocre security and performance, and may even be vulnerable to spam attacks due to security vulnerabilities. Switching to a more reliable public DNS service can significantly improve resolution security and speed.

Well-known public DNS services include 1.1.1.1 and Google's 8.8.8.8, as well as DNS.com, a global, one-stop infrastructure security service provider. These services are maintained by professional teams and generally offer stronger attack resistance and faster response times.

The modification method varies depending on the operating system. Windows users can change the automatic DNS acquisition to manual configuration in the Internet Protocol version 4 settings of the network adapter properties, entering the preferred and alternate DNS addresses. Mac users can perform similar operations in the Network pane of System Preferences. Modifying a mobile device is more complex, but installing a dedicated app simplifies the process. It's important to note that modifying the DNS for a device only affects that device. To protect your entire home network, you can modify the DNS globally in your router settings, benefiting all connected devices.

For users seeking a higher level of security, traditional DNS can be enhanced with authentication and encryption between the client and resolver, effectively preventing query hijacking. While the configuration process is relatively complex and requires installing a dedicated client and selecting a supported service provider, the security benefits are significant.

Virtual private networks (VPNs) are one of the ultimate solutions to combat DNS pollution. All network traffic (including DNS queries) is routed through an encrypted tunnel to a remote server, which then initiates DNS resolution. This method not only hides the user's true IP address but also prevents local network operators from interfering with the DNS process. Choosing a reputable service provider is crucial, as all your online activity will flow through their infrastructure. Some services also offer proprietary DNS leak prevention features to ensure queries don't accidentally bypass the encrypted tunnel.

Scenarios-Specific Solutions: Modifying the Hosts File and Browser Settings

For frequently visited websites, modifying the Hosts file is an immediate anti-pollution measure. The Hosts file is a table of domain name and IP address mappings stored locally on the operating system, taking precedence over DNS queries. Manually adding the correct resolution record can completely bypass the DNS system.

To do this, obtain the target website's real IP address (using an overseas server's ping command or online tools), then edit the system's Hosts file (located in C:\Windows\System32\drivers\etc on Windows and /etc/hosts on Mac/Linux) with administrator privileges and add a line in the "IP address domain name" format. This method is accurate and effective, but it's costly to maintain and isn't suitable for websites that use CDNs or frequently change IP addresses.

Browser-level protection settings are also available. For example, in Firefox, users can set network.trr.mode to 2 in the about:config page to force DoH resolution. Enabling DNS over HTTPS can also effectively prevent ISP hijacking. These browser-level settings take precedence over system settings, providing users with flexible configuration options.

Combined Strategies and Daily Protection Awareness

No single solution can provide 100% protection; a layered approach is the wisest choice. It's recommended to use encrypted DNS as a foundational layer of protection, combined with a reliable virtual private network for sensitive operations, and to use a hosts file for fixed resolution of critical websites. Furthermore, keeping your operating system and browser up to date is crucial, as security patches often include fixes for DNS-related vulnerabilities.

Cultivating good internet habits is equally important. Be wary of browser certificate warnings, which may signal a man-in-the-middle attack; regularly check your network settings to prevent malware from tampering with your DNS configuration; use DNS protection provided by your internet security software; and remain vigilant against unusual pop-ups and redirects.

By combining and applying these practical technologies, ordinary users are fully capable of building an effective personal protection system. Autonomy in the digital age means not only freedom of access but also the security control of basic network services.