Scraping always failing? Check DNS before switching proxies.

<p style="line-height: 2;"><span style="font-size: 16px;">If you work in</span><span style="color: rgb(9, 109, 217); font-size: 16px;"> </span><a href="https://www.b2proxy.com/use-case/market" target="_blank"><span style="color: rgb(9, 109, 217); font-size: 16px;">market research</span></a><span style="font-size: 16px;">, ad verification, or SEO monitoring, you may have encountered this strange situation: the proxy IP tests fine, the browser can open web pages, but when you run your data collection script, eight out of ten requests fail. Sometimes you wait forever and finally get a "connection timeout."</span></p><p style="line-height: 2;"><span style="font-size: 16px;">When this happens, most people's first reaction is that the proxy is broken, so they rush to switch to another one. But after switching several times, the problem persists. At this point, the issue is likely not the proxy itself, but a fundamental step you've overlooked: DNS resolution.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">Today, let's talk about how DNS resolution can cause data collection failures, and how to troubleshoot it quickly.</span></p><p style="line-height: 2;"><br></p><h2 style="line-height: 2;"><span style="font-size: 24px;"><strong>What Is DNS Resolution?</strong></span></h2><p style="line-height: 2;"><span style="font-size: 16px;">Think of it like this: you want to go to a place, but you only know the name of the building, not its exact address. DNS resolution is like asking for directions, helping you translate a domain name (such as example.com) into an IP address (such as 93.184.216.34).</span></p><p style="line-height: 2;"><span style="font-size: 16px;">The data collection process is the same. Your code contains a domain name, but network transmission requires an IP address. If DNS resolution fails at this step, the request cannot be sent out, and no matter how perfectly the proxy is configured, it won't help.</span></p><p style="line-height: 2;"><br></p><h2 style="line-height: 2;"><span style="font-size: 24px;"><strong>DNS Resolution in Proxy Scenarios: Two Modes</strong></span></h2><p style="line-height: 2;"><span style="font-size: 16px;">This is where confusion easily arises. When you use a proxy IP, DNS resolution works in two completely different ways.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">The first is local resolution. Your computer first resolves the domain name into an IP address itself, then tells the proxy server, "Connect to this IP for me." If the local DNS server responds slowly, or the resolved IP is inaccurate, the request gets stuck before it even leaves.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">The second is remote resolution. Your computer sends the domain name directly to the proxy server, and the proxy server handles the resolution. This approach better matches the network environment of the target region, but it requires the proxy server's DNS configuration to be stable.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">Many data collection failures occur because the wrong mode is used. For example, if you need to obtain localized content from a website in a certain region, but you use local resolution, you might end up with a CDN node far away from the target server. Not only is it slow, but the returned content may also be incorrect.</span></p><p style="line-height: 2;"><br></p><h2 style="line-height: 2;"><span style="font-size: 24px;"><strong>How to Tell If DNS Is the Problem</strong></span></h2><p style="line-height: 2;"><span style="font-size: 16px;">If you encounter the following situations, DNS resolution is very likely the culprit.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">The first situation is that some websites are accessible, while others simply won't connect. This is usually because DNS resolution for certain domain names is unstable, working sometimes and failing other times.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">The second situation is that requests are sent but there is no response for a long time, eventually resulting in a timeout. If local DNS resolution takes more than a few seconds without a result, the request gets stuck at the very first step.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">The third situation is that the same domain name is sometimes accessible and sometimes fails. This is a typical sign of DNS cache expiration or resolution result drift.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">The fourth situation is that the browser can open the page, but the collection program cannot connect. Browsers may have independent DNS caches or longer timeout settings, while collection programs tend to be more sensitive.</span></p><p style="line-height: 2;"><br></p><h2 style="line-height: 2;"><span style="font-size: 24px;"><strong>How to Troubleshoot DNS Resolution Issues</strong></span></h2><p style="line-height: 2;"><span style="font-size: 16px;">The troubleshooting method is actually not complicated, and you can do it without writing code.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">Step one: manually test domain name resolution on your computer. Open the command-line tool, enter the resolution command, and see whether the domain name can be translated into an IP address normally, and how long it takes. If this step gets stuck, it means there is a problem with local DNS.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">Step two: try switching to a public DNS. If the resolution speed becomes noticeably faster after switching to a more stable public DNS, then the problem lies with the original DNS server.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">Step three: enable remote resolution in the proxy configuration. If you are using a SOCKS5 proxy, change the address type to domain mode, and let the proxy server handle the resolution. The advantage is that the resolution location is closer to the target website, making the results more accurate.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">Step four: check whether the proxy service provider supports stable DNS resolution. Some proxy gateways have weak DNS configurations and frequently fail to resolve. In this case, consider switching to a provider with better network infrastructure in the target region.</span></p><p style="line-height: 2;"><br></p><h2 style="line-height: 2;"><span style="font-size: 24px;"><strong>How to Reduce Collection Failures Caused by DNS Resolution</strong></span></h2><p style="line-height: 2;"><span style="font-size: 16px;">First, use caching wisely. For domain names that need to be accessed repeatedly, caching the resolution result can avoid the delay caused by repeated resolution.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">Second, set a reasonable timeout. DNS resolution timeout should not be set too short or too long. Too short makes it easy to report false failures, while too long keeps tasks stuck and wastes time.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">Third, regularly verify resolution accuracy. Especially when doing multi-region market research, the same domain name may resolve to different IP addresses in different regions, which directly affects the content you see. Do spot checks regularly to ensure the resolution results meet expectations.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">Fourth, choose a proxy solution that supports remote resolution. For cross-border market research tasks, remote resolution is usually more reliable than local resolution and is closer to the real network environment of the target market.</span></p><p style="line-height: 2;"><br></p><h2 style="line-height: 2;"><span style="font-size: 24px;"><strong>Conclusion</strong></span></h2><p style="line-height: 2;"><span style="font-size: 16px;">There are many reasons why data collection fails, and proxy IP is only one part of it. Before suspecting the proxy, spend a few minutes troubleshooting DNS resolution. This can often save you a lot of time and cost from switching IPs and providers.</span></p><p style="line-height: 2;"><span style="font-size: 16px;">These technical approaches are commonly used in scenarios such as market research, ad verification, </span><a href="https://www.b2proxy.com/use-case/seo" target="_blank"><span style="color: rgb(9, 109, 217); font-size: 16px;">SEO monitoring</span></a><span style="font-size: 16px;">, and brand protection, with the goal of obtaining public, accurate information about target markets. Remember a simple principle: if domain name resolution doesn't work, even the best proxy is useless. Once you get the DNS layer sorted out, your collection success rate will improve noticeably.</span></p><p style="line-height: 2;"><span style="font-size: 16px;"> </span></p>