Common DNS Issues and How to Fix Them

DNS (Domain Name System) is essential for translating human-readable domain names into IP addresses that computers use. However, DNS can sometimes run into issues. Let’s go through some common DNS problems and how to resolve them.

1. DNS Server Not Responding

Symptoms: Websites won’t load, and you see a “DNS server not responding” error. Fix:

1. Restart Your Router: Turn off your router, wait for a few seconds, and turn it back on.
2. Change DNS Server: Change your DNS server to Google DNS (8.8.8.8 and 8.8.4.4) or OpenDNS (208.67.222.222 and 208.67.220.220).

2. DNS Cache Poisoning

Symptoms: You’re redirected to malicious websites. Fix:

1. Flush DNS Cache: Open Command Prompt as an administrator and type ipconfig /flushdns.
2. Update DNS Server Software: Ensure your DNS server software is up-to-date.

3. DNS Propagation Delay

Symptoms: Newly updated DNS records are not resolving. Fix:

1. Wait for Propagation: DNS changes can take up to 48 hours to propagate.
2. Check TTL (Time to Live) Settings: Lower the TTL settings temporarily to speed up propagation.

4. Incorrect DNS Records

Symptoms: Website doesn’t load, or services like email are not working. Fix:

1. Verify DNS Records: Double-check your DNS records for any typos or incorrect settings.
2. Use DNS Lookup Tools: Tools like nslookup or online DNS checkers can help identify issues.

5. DNS Timeout

Symptoms: Website load times are very slow or fail to load. Fix:

1. Check Network Connectivity: Ensure your internet connection is stable.
2. Increase DNS Timeout Settings: Adjust the timeout settings in your DNS server configuration.

6. DNSSEC Issues

Symptoms: DNSSEC-enabled domains fail to resolve. Fix:

1. Check DNSSEC Configuration: Verify that DNSSEC settings are correct.
2. Update DNSSEC Keys: Ensure your DNSSEC keys are up-to-date and not expired.

General Tips

• Regularly Update: Keep your DNS server software and configurations up-to-date.
• Monitor DNS Performance: Use monitoring tools to keep an eye on your DNS server’s performance.
• Backup DNS Records: Regularly back up your DNS records to prevent data loss.

Troubleshooting Tools

• Ping: Test the connectivity between your device and the server.
• Traceroute: Identify the path your data takes to reach the server.
• Dig: A more advanced DNS lookup tool than nslookup.