The most common cause of "service can't reach network" issues is DNS resolution failure. Here's a practical checklist to make your DNS stack bulletproof:
1. Use a reliable caching resolver Set up a local caching DNS (e.g. dnsmasq, Unbound) that validates DNSSEC. This reduces reliance on upstream providers and catches tampered records.
# Check your current resolver
cat /etc/resolv.conf
# Test resolution with timing
dig +trace example.com
# Validate DNSSEC chain
delv example.com2. Enable DNSSEC validation DNSSEC ensures records are authentic and haven't been tampered with. Enable it on your local resolver and verify the chain of trust.
3. Automate resolution checks Integrate periodic dig or nslookup checks into your monitoring stack. Alert when resolution latency exceeds threshold or fails entirely.
4. Test with multiple DNS providers Run regular tests against different DNS servers (e.g. 1.1.1.1, 8.8.8.8, 9.9.9.9) to identify single points of failure and plan for redundancy.
Pro tip: Add a synthetic DNS health check to your CI/CD pipeline. If DNS is down, fail the build early — don't let it ship to production.