Set DNS Servers, But the Website is Unreachable

If you’ve configured DNS servers but your website is still unreachable, it could be due to various DNS, network, or configuration issues. Here’s a guide to diagnosing and resolving problems when a site remains inaccessible despite setting DNS servers correctly.

1. Understanding DNS and How It Affects Website Accessibility

DNS (Domain Name System) servers translate domain names (like example.com) into IP addresses, allowing browsers to connect to websites. When DNS settings are incorrect or there are network issues, users may experience errors such as “Server Not Found” or “Website Unreachable.”

2. Common Causes of DNS Issues

There are several potential causes for DNS-related website inaccessibility:

• DNS Propagation Delay: DNS changes can take time to propagate worldwide, sometimes up to 48 hours.
• Incorrect DNS Records: Incorrectly configured A, CNAME, or MX records can prevent a site from resolving correctly.
• DNS Cache: Cached DNS records in your browser or operating system may still point to outdated IP addresses.
• Firewall and Network Issues: Firewalls or network restrictions may block access to certain IP addresses.

3. Troubleshooting Steps

Step 1: Verify DNS Propagation

When you update DNS settings, propagation can take time. To check if DNS changes have propagated, use a DNS propagation tool such as WhatsMyDNS:

• Go to WhatsMyDNS and enter your domain name.
• Check if the IP address resolves correctly across different locations.

If the correct IP address shows up inconsistently, give the propagation time to complete.

Step 2: Clear DNS Cache

Cached DNS records can cause browsers to use outdated IP addresses. Clearing the cache on your operating system and browser can resolve this.

To clear DNS cache on different systems:

• Windows:
  ipconfig /flushdns
• MacOS:
  sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
• Linux (varies by distribution, here’s an example for Ubuntu):
  sudo systemd-resolve –flush-caches

Clear Browser Cache: Go to your browser settings, locate “Clear browsing data,” and ensure the cache is cleared.

Step 3: Check DNS Configuration with nslookup and dig

Using command-line tools like nslookup and dig can help verify if DNS records are correct.

• nslookup:
  nslookup example.com
• dig:
  dig example.com

These commands should return the correct IP address for your domain. If they don’t, double-check your DNS settings.

Step 4: Verify DNS Records in Domain Registrar

Log into your domain registrar’s control panel and review DNS settings. Confirm that all required records are in place:

• A Record: Maps your domain to an IP address.
• CNAME Record: Redirects subdomains to the main domain.
• MX Record: Ensures proper email delivery.

Step 5: Check Web Server Configuration

If DNS records are correct but the website remains unreachable, the issue could be with your web server configuration. Common issues include:

• Web Server Offline: Check if the web server is running. Restart it if necessary.
  sudo systemctl status apache2 # for Apache sudo systemctl status nginx # for Nginx
• Firewall Blocking Requests: Ensure that firewall rules allow traffic on the correct ports (e.g., HTTP on port 80 and HTTPS on port 443).

Step 6: Test Network Connection and Firewall Settings

If you have network restrictions in place, ensure they aren’t blocking access to your domain.

• Ping Test: Run a ping test to see if the domain resolves to an IP and if packets are reaching the server.
  ping example.com
• Traceroute Test: Use traceroute (Linux/macOS) or tracert (Windows) to trace the route to the server. This helps identify where the connection fails.
  traceroute example.com

If the traceroute stops before reaching the server, there could be an issue with a specific network node.

4. Additional Solutions for DNS-Related Issues

• Switch DNS Servers: Try switching to a different DNS server, like Google DNS (8.8.8.8 and 8.8.4.4) or Cloudflare (1.1.1.1), on your computer or router.
• Disable Proxy or VPN: If using a proxy or VPN, temporarily disable it to rule out network interference.

5. Contact Your Hosting Provider

If none of the above steps resolves the issue, contact your hosting provider’s support team. They can verify server settings and provide specific recommendations or assist in diagnosing connectivity issues from their end.

Conclusion

Website inaccessibility, even after setting DNS servers, can be due to propagation delays, configuration errors, or network issues. By following these troubleshooting steps, you can identify and resolve the root cause, ensuring smooth access to your website.