A 404 Error is one of the most common HTTP status codes encountered on the web. It occurs when a user attempts to visit a webpage, but the server cannot locate the requested content. While the most common causes for a 404 error stem from missing files or broken links, DNS (Domain Name System) issues can also be responsible. These DNS-related 404 errors can occur when a website is unreachable or when domain resolution fails, preventing the browser from accessing the correct IP address.In this guide, we will explore how DNS issues can lead to 404 errors, the causes behind these issues, and how to troubleshoot and resolve them. By understanding the relationship between DNS and HTTP status codes like 404, you will be better equipped to handle and fix these errors effectively.

 Understanding the 404 Error

A 404 Not Found error is an HTTP status code that indicates that the server could not find the requested URL. This error is typically associated with problems on the web server, such as:

• The requested page has been deleted or moved.
• The URL was typed incorrectly.
• The web server is misconfigured or down.

In most cases, a 404 error is linked to the server not being able to locate the file, but this error can also manifest when DNS issues prevent the domain from being resolved correctly.

The Role of DNS in Website Access

DNS (Domain Name System) is the system that translates human-readable domain names like example.com into machine-readable IP addresses (e.g., 192.0.2.1). DNS is essentially the "address book" of the internet, allowing browsers to locate web servers by converting domain names into IP addresses.

When you type example.com into your browser, the following steps occur:

1. DNS Lookup: Your browser queries a DNS server to resolve example.com into its corresponding IP address.
2. Connecting to Server: Once the IP address is obtained, your browser connects to the server hosting example.com.
3. HTTP Request: Your browser sends an HTTP request for the webpage you requested.
4. Response: If everything is correct, the server sends back the requested content; otherwise, it may return a 404 error.

However, when DNS issues occur, the entire process can be interrupted, causing the server to be unreachable or misdirected. This can result in various types of errors, including 404 errors, even if the requested page actually exists.

How DNS Issues Can Lead to 404 Errors

When DNS issues arise, the browser may either fail to locate the website entirely or resolve the wrong IP address. Here are some specific ways DNS problems can lead to a 404 error:

 Incorrect DNS Records

If the DNS records for your domain are incorrect or misconfigured, the domain will not resolve to the correct web server, which can cause the browser to display a 404 error. The following DNS record issues are common:

• A Record Misconfiguration: An A record is responsible for pointing a domain to an IP address. If this record is incorrect or not set up properly, users may be directed to the wrong server or an inaccessible one.
• CNAME Record Errors: A CNAME record allows a domain or subdomain to point to another domain. If a CNAME is misconfigured, the browser may try to access a domain that doesn’t exist or resolve to an incorrect address.
• MX Record Misconfiguration: If you have mail servers configured on your domain, but the MX records are incorrectly set, this can sometimes affect other DNS resolution functions.

DNS Propagation Delays

DNS changes are not immediate. When you update your DNS records (e.g., moving your site to a new hosting provider or changing your DNS server), it can take anywhere from a few minutes to 48 hours for the updates to propagate across the internet. During this propagation period, users may still be directed to the old server, causing 404 errors if the content has been moved or deleted.

 DNS Server Issues

If your DNS server is down or unreliable, DNS requests may not be answered correctly. In this case, the browser may fail to resolve the domain name, resulting in errors like “Server Not Found” or 404 errors if the server is reachable but not responding as expected.

 Expired Domain or Incorrect Nameserver

If the domain has expired or if the nameservers are incorrectly configured (pointing to a non-existent DNS provider), users will be unable to resolve the domain and access the website, leading to 404 errors.

 Domain Forwarding or Redirection Problems

If your domain is set up with redirection (e.g., forwarding example.com to www.example.com) and the DNS settings are incorrect, users may be sent to a page that doesn’t exist, triggering a 404 error. Similarly, if you're using a URL redirect via CNAME or HTTP redirects and they are misconfigured, the user may end up on the wrong page.

 Diagnosing DNS-Related 404 Errors

Now that we understand the potential causes of DNS-related 404 errors, let’s dive into how to diagnose and troubleshoot these issues.

Check DNS Resolution with Tools

The first step in diagnosing DNS issues is to verify whether your domain is resolving correctly. You can use several online tools to check DNS records and ensure that your domain is correctly pointing to the appropriate IP address:

• WhatsMyDNS: This tool allows you to check how your domain is propagating across different DNS servers worldwide.
• MXToolbox: Provides DNS lookup tools for various types of DNS records, including A, MX, and CNAME records.
• NSLookup: A command-line tool for querying DNS records. It can help you determine whether your domain is resolving to the correct IP address.

If these tools indicate that the domain is resolving incorrectly (e.g., pointing to an old IP address or not resolving at all), you can take steps to update your DNS records.

 Verify DNS Records

Use your domain registrar or DNS hosting provider’s control panel to check the DNS records associated with your domain. Look for the following:

• A Records: Ensure the A record points to the correct IP address of your web server.
• CNAME Records: Verify that any subdomains are pointing to the correct domain or server.
• NS Records: Confirm that the nameservers are correctly set to your DNS provider.
• MX Records: If you're troubleshooting email issues alongside DNS issues, check MX records to ensure they’re pointing to the right mail servers.

Check for DNS Propagation Delays

If you’ve recently made changes to your DNS settings (such as updating the A record), be aware that it may take some time for the changes to propagate. You can check DNS propagation using online tools like DNSChecker.org to confirm whether the new settings have been applied globally.

If you're in the middle of a DNS change, wait up to 48 hours for full propagation before troubleshooting further.

Test Domain Access

Perform basic tests to determine whether the issue is related to DNS or the web server itself:

1. Ping the Domain: Open a command prompt (Windows) or terminal (macOS/Linux) and run the command ping example.com. If the domain resolves and responds with an IP address, it means the domain is accessible, and the issue likely lies with the server or web page.
2. Traceroute: A traceroute can show the network path your request takes to reach the server. If the traceroute stops or fails at any point, it may indicate a routing or DNS resolution problem.
3. Try Different Networks: Sometimes, DNS issues can be network-specific. Test your website on different networks (e.g., your mobile data, a VPN, or a different Wi-Fi network) to determine if the issue is with a particular ISP or DNS provider.

 Review Server Logs and Configuration

Once you confirm that DNS is resolving correctly, the issue may be with the server configuration or missing content on the server. Review your web server’s logs (e.g., Apache or Nginx logs) for any 404 errors related to missing files or incorrect URL mappings.

• Check for URL Redirection Issues: Verify that your server’s redirection rules (if any) are correctly configured. Incorrect redirect chains or infinite loops can sometimes cause 404 errors.

 Confirm Domain Expiry or Renewal Status

If DNS resolution fails, check if your domain has expired or if the renewal was missed. You can check your domain’s expiration date through your domain registrar or use services like Whois Lookup to verify the registration status.

 Resolving DNS-Related 404 Errors

Once you’ve identified the source of the DNS-related issue causing the 404 error, follow these steps to resolve it:

 Correct DNS Records

Update any incorrect DNS records to ensure they point to the correct IP address or web server. If your A record is pointing to the wrong server, update it to reflect the correct IP. For example, change:

• Old A record: example.com -> 192.0.2.100
• New A record: example.com -> 192.0.2.200

 Update Nameservers

If your domain is not using the correct nameservers, update the NS records to point to the correct DNS provider. You can typically find this information in your hosting or DNS provider's documentation.

Wait for DNS Propagation

After making changes to DNS records or nameservers, allow up to 48 hours for the changes to propagate worldwide. You can use WhatsMyDNS to monitor propagation progress.

Verify Server Configuration

Check your web server’s configuration for issues like missing content, broken redirects, or misconfigured virtual hosts. Ensure that all necessary files are in place and accessible.

 Renew Your Domain

If your domain has expired, renew it immediately with your domain registrar to restore access to your website.

Check SSL/TLS Configuration

If you’ve recently configured SSL/TLS certificates for HTTPS, make sure that the domain is properly resolving to the correct HTTPS endpoint. Misconfigured SSL/TLS certificates can sometimes trigger 404 errors if users are directed to insecure HTTP endpoints.

Usage Field for Troubleshooting 404 Errors Due to DNS Issues

Corporate Websites

• Usage: A company’s website, such as an e-commerce platform or informational site, relies heavily on DNS configuration to make the website accessible to customers.
• Problem: DNS misconfigurations (like wrong A records or CNAME records) can cause the site to be unreachable or lead to 404 errors for subdomains or pages that are supposed to exist.

Small Business Websites

• Usage: Small business websites use custom domains to establish their online presence, typically with minimal IT support.
• Problem: Misconfigured DNS settings or expired domains can cause 404 errors, affecting customer access.

Blog and Personal Portfolios

• Usage: Bloggers or portfolio creators use custom domains (e.g., myblog.com) to give their websites a professional appearance.
• Problem: DNS propagation delays or incorrect A records can lead to users being directed to a non-existent site, showing 404 errors.

Educational Institutions

• Usage: Universities and schools often set up custom domains for their student portals, learning management systems (LMS), and websites.
• Problem: Incorrectly configured MX records or A records could disrupt DNS resolution, leading to 404 errors when students or faculty try to access specific resources or pages.

News Websites

• Usage: News websites rely on rapid DNS updates to accommodate high traffic and content changes.
• Problem: If DNS settings aren’t updated correctly or if there are issues with the CNAME or NS records, users may be shown a 404 error instead of the intended article or page.

SaaS (Software as a Service) Platforms

• Usage: SaaS platforms use custom domains to provide each user with a personalized URL (e.g., customername.saasapp.com).
• Problem: If DNS settings are misconfigured, such as incorrect A records or CNAME entries, users may receive a 404 error when accessing their platform.

Nonprofit Organizations

• Usage: Nonprofits set up websites and donation pages under their custom domains to increase visibility and engagement.
• Problem: If there is a mismatch in DNS records or if DNS servers fail to propagate correctly, the nonprofit website may return a 404 error.

Freelancers and Consultants

• Usage: Freelancers set up professional websites with custom domains to promote their services and portfolios.
• Problem: Misconfigured A records or nameserver issues can cause 404 errors when potential clients try to access their websites.

Reseller Hosting Companies

• Usage: Hosting resellers provide custom domain hosting to clients under their own branded domain.
• Problem: If DNS records aren’t updated correctly or the NS records are incorrect, clients may see 404 errors when trying to access their websites.

Online Marketplaces (e.g., eBay, Etsy)

• Usage: Online marketplace sites require DNS configuration to direct users to different store pages.
• Problem: DNS issues, such as incorrect A records or expired domains, can cause 404 errors for sellers or customers trying to access specific listings.

Technical Issues Causing 404 Errors Due to DNS

Incorrect DNS Records

• Issue: Incorrect A records or CNAME records can prevent the domain from resolving to the correct web server.
• Solution: Verify and correct A records to point to the correct IP address. For subdomains, ensure the CNAME records are correctly configured to point to the main domain or server.

 DNS Propagation Delays

• Issue: After updating DNS records (such as A records or NS records), changes can take anywhere from a few minutes to 48 hours to fully propagate across the internet.
• Solution: Wait for full DNS propagation or check propagation status using tools like DNSstuff or WhatsMyDNS.

 Expired Domain

• Issue: If the domain has expired, DNS servers will not be able to resolve it, leading to 404 errors.
• Solution: Ensure that your domain is renewed on time. Use Whois lookup to check your domain’s expiration date.

Incorrect Nameservers

• Issue: If your domain’s NS records are pointing to the wrong nameservers, the domain may not resolve correctly, leading to 404 errors.
• Solution: Check the NS records to make sure they are pointing to the correct DNS provider and nameservers.

 Server Misconfiguration

• Issue: If the server is misconfigured or the URL is redirected incorrectly, the server may return a 404 error even though the domain resolves correctly.
• Solution: Check server logs for misconfigurations or faulty redirects. Ensure that URLs are correctly mapped in the web server’s configuration files (e.g., Apache, Nginx).

Missing or Moved Content

• Issue: Sometimes, DNS resolution works correctly, but content on the server (like pages or files) has been moved or deleted, causing a 404 error.
• Solution: Ensure that the requested content exists at the specified URL, and update any redirects if necessary.

 Caching Issues

• Issue: Cached DNS or web content can cause 404 errors if an old DNS resolution or content version is being used.
• Solution: Clear your browser cache and flush your DNS cache on your local machine (ipconfig /flushdns on Windows or sudo killall -HUP mDNSResponder on macOS).

 DNS Server Down

• Issue: If the DNS provider’s server is down, the domain may not resolve properly, causing a 404 error.
• Solution: Check your DNS provider’s status page for outages. If necessary, switch to a backup DNS provider.

DNS Lookup Failures

• Issue: Sometimes, DNS queries fail to resolve due to server misconfigurations or network issues, causing DNS failures and 404 errors.
• Solution: Use tools like NSLookup or MXToolbox to perform DNS diagnostics and identify lookup failures.

 Domain Redirect Misconfiguration

• Issue: If there’s an incorrect URL redirect (such as a 301 or 302 redirect) configured in DNS or at the server level, it may point to a non-existent page.
• Solution: Check redirection rules and update them to ensure they’re pointing to the correct, existing pages on the server.

Technical FAQ for Troubleshooting 404 Errors Due to DNS Issues

 What is DNS, and how does it affect 404 errors?

• Answer: DNS (Domain Name System) translates human-readable domain names (like example.com) into IP addresses. A 404 error typically occurs when a server cannot find the requested page. If DNS fails to resolve the domain to the correct server, or if DNS records are misconfigured, the browser may not find the server or the correct page, leading to a 404 error.

 How do I check if DNS is causing a 404 error?

• Answer: Use DNS diagnostic tools like WhatsMyDNS, MXToolbox, or NSLookup to ensure that your domain resolves to the correct IP address. If DNS resolution is failing, this could be the cause of the 404 error.

 Can DNS propagation delays cause a 404 error?

• Answer: Yes. When you update DNS records (like A records or CNAME records), it can take time for the changes to propagate. During this period, users may still be directed to the old server, causing a 404 error if the page has been moved or deleted.

What should I do if my domain’s DNS records are not updating?

• Answer: Ensure you’ve correctly configured your DNS settings with your hosting provider or registrar. If propagation is delayed, wait up to 48 hours. You can also try flushing your local DNS cache to force your computer to look up the most recent DNS information.

 What are the most common DNS records involved in a 404 error?

• Answer: The most common DNS records involved are A records (which point the domain to an IP address) and CNAME records (which alias one domain to another). Misconfigured or missing records for these types can result in 404 errors if the domain doesn’t resolve correctly.

 How do I fix an expired domain causing a 404 error?

• Answer: To resolve an expired domain, you need to renew it with your domain registrar. Once the domain is active again, DNS will resolve correctly, and the 404 error should disappear.

 How do I clear DNS cache on my computer?

• Answer: On Windows, open Command Prompt and type ipconfig /flushdns. On macOS, open Terminal and type sudo killall -HUP mDNSResponder. This will clear your local DNS cache and force the computer to retrieve fresh DNS records.

Can server-side misconfigurations cause DNS-related 404 errors?

• Answer: Yes, if your server is misconfigured (for example, incorrect redirects or missing files), it may respond with a 404 error even if DNS resolution works correctly. Check the server logs for issues related to misconfigured URLs or missing content.

 How can I prevent DNS-related 404 errors in the future?

• Answer: Regularly monitor your DNS records and domain expiration status. Avoid frequent changes to DNS settings, and ensure that all URLs on your website are correctly mapped. Additionally, use DNS monitoring tools to stay on top of potential issues.

 Should I contact my DNS provider if I encounter a 404 error?

• Answer: Yes, if you suspect that DNS issues are causing the 404 error, contacting your DNS provider can help identify problems with the DNS resolution process. If DNS is working correctly, then you may need to troubleshoot server-side issues.