Add DNS error logging and server diagnostic script

- Enhanced MongoDB connection error handling with DNS-specific logging
- DNS resolution errors now display clear diagnostic messages
- Added diagnose-server.sh script for remote server troubleshooting
- Graceful degradation continues when database connection fails

backend/diagnose-server.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+
+echo "=========================================="
+echo "Backend Diagnostic Script for 10.0.10.30"
+echo "=========================================="
+echo ""
+
+echo "1. Checking Docker containers..."
+docker ps --filter "name=normogen" --format "table {{.Names}}	{{.Status}}	{{.Ports}}"
+echo ""
+
+echo "2. Checking if port 6500 is listening..."
+sudo ss -tlnp | grep 6500 || echo "Port 6500 NOT listening"
+echo ""
+
+echo "3. Checking firewall status..."
+sudo ufw status || echo "UFW not installed"
+echo ""
+
+echo "4. Checking Docker network..."
+docker network ls | grep normogen
+echo ""
+
+echo "5. Backend container logs (last 20 lines)..."
+docker logs --tail 20 normogen-backend-dev 2>&1
+echo ""
+
+echo "6. Testing local connection..."
+curl -s --max-time 3 http://localhost:6500/health || echo "Local connection failed"
+echo ""
+
+echo "7. Testing container connection..."
+docker exec normogen-backend-dev curl -s --max-time 3 http://localhost:8000/health || echo "Container connection failed"
+echo ""
+
+echo "=========================================="
+echo "Diagnostic complete"
+echo "=========================================="