Domain DNS Resolution Troubleshooting: Common Causes and Solutions for Website Inaccessibility

DNS resolution issues are the most common cause of "website cannot be accessed" errors. This article will help you systematically troubleshoot DNS-related problems.

1. Common DNS Fault Types

Fault Type Symptoms Cause
Domain Not Resolved Browser shows server not found DNS record not configured or not yet active
Resolved to Wrong IP Visiting the wrong site DNS record configured incorrectly
Slow Resolution Website loads slowly Slow DNS server response
Partial Region Inaccessibility Accessible in some regions Incomplete DNS propagation

2. Diagnostic Tools

# Basic DNS lookup
nslookup example.com
nslookup -type=MX example.com

# Detailed DNS lookup
dig example.com
dig @8.8.8.8 example.com  # Use specified DNS server

# Route tracing
traceroute example.com

# Check DNS propagation
# Online tool: whatsmydns.net

3. Common Issues and Solutions

Issue Solution
DNS record not active Wait 24-48 hours for propagation
NS record error Verify DNS server configuration
TTL set too high Lower TTL to speed up switching
DNSSEC configuration error Check DNSSEC signatures

4. Preventive Measures

  1. Use a reliable DNS service provider
  2. Set appropriate TTL values
  3. Monitor DNS resolution status
  4. Configure multiple NS records
  5. Enable DNSSEC for security