Internet connection suddenly seized to work properly and I don’t know why. DNS issues

Understanding and Troubleshooting DNS Connectivity Issues: A Comprehensive Guide

Experiencing sudden internet connectivity problems can be frustrating, especially when your usual troubleshooting efforts don’t yield immediate results. Recently, a user encountered a specific issue related to DNS (Domain Name System) errors, which disrupted their broadband connection after years of stable service. This article aims to provide a detailed overview of common DNS troubleshooting steps and best practices for resolving such issues.

Identifying the Problem

The user reported error messages indicating DNS server unavailability, such as:

• “Your DNS server might be unavailable.”
• “Your computer appears to be correctly configured but the device detected or resource DNS server is not responding.”

These messages suggest that while the network configuration may seem correct, the system is unable to contact a DNS server, leading to web access failures. Symptoms like these can arise due to misconfigurations, network issues, or problems with the DNS servers themselves.

Initial Troubleshooting Steps

1. Restarting Hardware:

2. The user unplugged and rebooted their router, a fundamental step to resolve temporary glitches. However, this alone did not fix the issue, indicating that more specific troubleshooting was necessary.

3. Verifying Network Configuration:

4. One common technique involves adjusting DNS server settings on your computer. For Windows systems, this means modifying the IPv4 properties:

   • Access Network Connection Settings.
   • Select the relevant network adapter.
   • Navigate to Properties > Internet Protocol Version 4 (TCP/IPv4).
   • Manually set DNS servers to known public addresses, such as:
   • Google DNS: 8.8.8.8 and 8.8.4.4
   • Cloudflare DNS: 1.1.1.1 and 1.0.0.1

5. Command-Line Tools for Troubleshooting:

6. The following commands can help clear cached DNS data and reset network settings:
   • ipconfig /flushdns — Clears DNS resolver cache.
   • netsh winsock reset — Resets the Windows Socket API, which can resolve socket-related connectivity issues.

Implementing these steps can often resolve DNS-related problems. Modifying DNS addresses to reliable public DNS servers is a common and effective workaround.

Additional Recommendations

• Check Your Internet Connection:
• Confirm that other devices can connect to the internet. If all devices are affected, the issue likely resides with the router or the ISP.

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