domain-management（域管理）

Domain Management Skill

This skill helps you manage domains and DNS configuration for the SG Cars Trends platform.

When to Use This Skill

• Configuring custom domains in Vercel
• Debugging domain resolution issues
• Setting up redirects
• Troubleshooting SSL/TLS errors

Domain Architecture

Domain Structure

sgcarstrends.com                    # Production web app
*.vercel.app                        # Preview deployments

DNS Provider: Vercel

Vercel handles DNS management with automatic SSL certificates.

Features:

• Automatic SSL/TLS certificates
• Global edge network
• Fast DNS propagation
• Built-in DDoS protection

Vercel Domain Configuration

Adding Custom Domain

1. Go to Vercel Dashboard → Project Settings → Domains
2. Add sgcarstrends.com
3. Follow DNS configuration instructions
4. Vercel automatically provisions SSL certificate

DNS Records

Point your domain to Vercel:

Type    Name    Value
A       @       76.76.21.21
CNAME   www     cname.vercel-dns.com

Or use Vercel nameservers for full DNS management.

Debugging DNS Issues

Check DNS Propagation

# Check DNS resolution
dig sgcarstrends.com
dig @8.8.8.8 sgcarstrends.com

# Or use online tools
# https://www.whatsmydns.net/#A/sgcarstrends.com

Check SSL Certificate

# Check certificate details
openssl s_client -connect sgcarstrends.com:443 -servername sgcarstrends.com

# Check certificate expiry
echo | openssl s_client -connect sgcarstrends.com:443 2>/dev/null | openssl x509 -noout -dates

Test Domain Resolution

# Test HTTPS
curl -I https://sgcarstrends.com

# Test redirect (www → apex)
curl -I https://www.sgcarstrends.com

Common Issues

Issue: DNS not resolving Solutions:

1. Check DNS records in Vercel dashboard
2. Verify nameserver configuration
3. Wait for propagation (usually < 5 minutes)

Issue: SSL certificate error Solutions:

1. Check domain is verified in Vercel
2. Wait for certificate provisioning (up to 24 hours)
3. Check domain DNS points to Vercel

Issue: 404 on custom domain Solutions:

1. Verify domain is added to correct project
2. Check deployment is successful
3. Verify build output

Security Headers

Configure in next.config.ts:

const securityHeaders = [
  {
    key: "Strict-Transport-Security",
    value: "max-age=63072000; includeSubDomains; preload",
  },
  {
    key: "X-Frame-Options",
    value: "SAMEORIGIN",
  },
  {
    key: "X-Content-Type-Options",
    value: "nosniff",
  },
];

const nextConfig = {
  async headers() {
    return [
      {
        source: "/:path*",
        headers: securityHeaders,
      },
    ];
  },
};

References

• Vercel Domains: https://vercel.com/docs/projects/domains
• Vercel DNS: https://vercel.com/docs/projects/domains/dns

Best Practices

1. Use Apex Domain: sgcarstrends.com for cleaner URLs
2. HTTPS Only: Vercel enforces HTTPS automatically
3. www Redirect: Configure www → apex redirect
4. Monitor: Check Vercel dashboard for domain status