In website management and network architecture, domain name resolution is a crucial step, determining whether users can access the correct server after entering a domain name in their browser. However, in practice, domain name resolution errors are a common and troublesome problem, especially when the domain name resolves to an incorrect IP address. This can not only prevent users from accessing the website but also impact a company's online services and reputation. The core of the domain name resolution process lies in the DNS system, which translates human-readable domain names into machine-understandable IP addresses, enabling users to access the correct server through the domain name. Simply put, domain name resolution is the process of mapping a requested domain name to one or more IP addresses through a DNS server. The DNS resolution process involves multiple stages, from DNS records to local caching, and errors can occur at any stage, leading to the wrong IP address being pointed to.

　　First, understanding the DNS resolution process is the first step in troubleshooting. When a user enters a domain name, the browser sends a request to a DNS server to query the IP address corresponding to the domain name. The DNS resolution process typically involves multiple levels, including root DNS servers, top-level domain DNS servers (such as .com, .net, etc.), and authoritative DNS servers. Each level of DNS server stores a portion of the domain name-to-IP address mapping records, ultimately returning an IP address to the user. If a DNS record is misconfigured or a problem occurs in any link, the user may access an incorrect IP address, causing the website to fail to load correctly or become inaccessible.

　　The most common cause of domain name resolution errors is misconfigured DNS records. In DNS, the mapping relationship between domain names and IP addresses is maintained through A records (IPv4 addresses) and AAAA records (IPv6 addresses). When DNS records are misconfigured, the server's domain name will resolve to an incorrect IP address. This situation typically occurs in the following scenarios: First, the domain name resolution configuration is not updated in the DNS service provider's management backend; second, an incorrect IP address is manually entered or incorrectly pointed to in the configuration file; third, the DNS server in the domain name forwarding chain is faulty or improperly configured, causing the request to be incorrectly redirected to another server. To resolve this type of problem, you first need to log in to the DNS management backend and check the configuration of the A record or AAAA record to confirm that it correctly points to the target server's IP address.

　　If the DNS records are correct, but the correct IP address still cannot be resolved, the problem might be due to DNS caching. DNS caching is a mechanism designed to improve resolution efficiency; it caches the results of recently accessed domain name resolutions locally or on a DNS server. When a user accesses the same domain name again, the DNS system can directly use the cached result without re-initiating a resolution request. However, DNS caching can also cause delays in resolution results, especially after DNS records are updated. The cached old records may continue to be used, leading to accessing the wrong IP address. In this case, the problem can be solved by clearing the local cache or refreshing the DNS cache. For individual users, the local cache can be cleared using command-line tools; for example, in Windows, running the command `ipconfig /flushdns` will clear the local DNS cache. For servers or corporate network environments, the problem can be solved by restarting the DNS service or manually clearing the DNS server's cache.

　　Besides local caching, DNS resolution errors can also be related to browser caching. When DNS resolution results are returned and loaded into the browser, the browser caches these results to speed up subsequent visits. If the DNS records are updated at this time, the browser may still use the cached old resolution results, causing the user to access the wrong IP address. The solution to this problem is to clear your browser cache or force refresh the page. In most browsers, you can force refresh by pressing Ctrl + F5 to avoid loading cached DNS resolution results.

　　If the above troubleshooting steps do not resolve the issue, the problem may lie with the DNS server itself. DNS server misconfigurations, malfunctions, or network problems can cause inaccurate domain name resolution results or return incorrect IP addresses. In this case, you can use third-party DNS tools, such as dig or nslookup, to check if the DNS resolution process is normal and to examine the resolution results returned by each DNS server. If the returned IP address does not match the expectation, it may be due to a DNS server malfunction or configuration problem. In this case, you can contact your DNS service provider to check and repair the server malfunction or configuration error.

　　In some special cases, DNS resolution errors may also be caused by DNS hijacking or DNS poisoning. DNS hijacking refers to a malicious third party modifying DNS requests or responses to cause users to access malicious websites, usually for the purpose of stealing user privacy information or conducting network attacks. DNS poisoning occurs in certain countries or regions where DNS resolution results are deliberately tampered with to block or interfere with access to certain websites. In such cases, users can use secure DNS resolution services to avoid DNS hijacking and pollution.

　　Through the above troubleshooting steps, users can resolve most domain name resolution errors caused by incorrect DNS record configuration, DNS caching, or server failures. To better troubleshoot and resolve issues, users can also take preventative measures during website deployment. For example, regularly check DNS record configurations to ensure IP addresses match the actual servers; use CDN acceleration services to reduce reliance on DNS resolution and improve access speed and stability; and choose a stable and reliable DNS service provider to ensure the continuous availability of resolution services.

　　FAQs:

　　1. Why can't I access the new server after updating DNS records?

　　A: This may be due to an outdated DNS cache. Please try clearing your local cache and refreshing your browser cache, or wait for the DNS's TTL (Time to Live) to expire.

　　2. How do I check if DNS records are configured correctly?

　　A: You can use the nslookup or dig command to query the domain name resolution results and confirm whether the resolved IP address is correct.

　　3. Why do domain name resolution errors sometimes occur, even affecting multiple users?

　　A: This may be caused by DNS server malfunction or misconfiguration, especially when DNS resolution requests pass through multiple DNS servers; a problem at any stage can affect the result.

　　4. How to prevent DNS hijacking?

　　A: You can choose to use a reliable DNS resolution service and enable DNSSEC (DNS Security Extensions) to enhance security.

　　5. How to avoid the impact of DNS resolution problems?

　　A: Regularly check DNS records, use CDN acceleration services, choose a reputable DNS service provider, and ensure timely updates of DNS records.