Cloud network issues often involve security rules, routing, or DNS.
Connectivity checklist:
Verify security groups allow traffic
Check NACL rules both directions
Confirm route tables have correct entries
Ensure gateways exist
Verify target is running
Useful tools:
- VPC Reachability Analyzer
- VPC Flow Logs
- CloudWatch metrics
Common issues:
- Different security groups on response path
- Missing route table entries
- NACL blocking ephemeral ports
- Wrong DNS resolution
Document your architecture. Diagrams speed troubleshooting.