# Quick Technical Note — Northwind Logistics: Internal Panel Inaccessible After Update

**Generated on:** 2026-05-15
**Author:** Auto-generated via MCP / n8n
**Severity:** High — affects multiple employees
**Status:** Under diagnosis

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## 1. Infrastructure Architecture

| Component | Description |
|---|---|
| **Company** | Northwind Logistics (small logistics company) |
| **OS** | Ubuntu Server |
| **Orchestration** | Docker with Docker Compose |
| **Database** | PostgreSQL |
| **Application** | Internal Node.js panel |
| **Automation** | n8n (administrative processes and reports) |
| **Reverse Proxy** | Nginx / Traefik |
| **Access** | Internal web panel for employees |

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## 2. Incident Description

After an overnight update, **several employees report being unable to access the Northwind Logistics internal panel**. Docker containers show `UP` status, but the web service isn't responding correctly. The problem appears to be in **service accessibility**, not container availability.

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## 3. Initial Hypotheses

| # | Hypothesis | Affected area |
|---|---|---|
| 1 | The reverse proxy (Nginx/Traefik) isn't correctly forwarding traffic to the Node.js service after the update | Network / Proxy |
| 2 | The Node.js process inside the container has crashed or is in an `unhealthy` state | Application |
| 3 | The update changed file permissions, environment variables, or PostgreSQL connection configuration | Permissions / Config |
| 4 | PostgreSQL isn't accepting connections (blocked port, changed credentials, max connections reached) | Database |
| 5 | The exposed port changed or Ubuntu's firewall is blocking external access | Network / Firewall |

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## 4. Useful Diagnostic Commands

```bash
# Check actual container status
docker compose ps

# Review Node.js application logs
docker compose logs node-app --tail 50

# Check reverse proxy status
systemctl status nginx          # or traefik

# Test internal accessibility
curl -v http://localhost:<port>/health

# Check listening ports and associated processes
ss -tulpn

# Review proxy system logs
journalctl -u nginx --since "1 hour ago"

# Check container network config and healthcheck
docker inspect <container-id>

# Test PostgreSQL connection
psql -h localhost -U <user> -d <db> -c "SELECT 1"
```

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## 5. Quick Checklist

- [ ] Describe the case clearly
- [ ] Identify the affected environment
- [ ] Collect relevant evidence or logs
- [ ] Define verifiable hypotheses
- [ ] Test one minimal action
- [ ] Validate the result
- [ ] Save or share the note if applicable

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*Note generated as a quick technical structure from an MCP tool exposed by n8n.*