smom-dbis-138/frontend-dapp/TROUBLESHOOTING.md

# Troubleshooting Connection Timeout - 192.168.11.211

## Issue
Connection timeout when accessing `http://192.168.11.211/`

## Server Status ✅

All server-side checks pass:
- ✅ VM (2101) is running
- ✅ Nginx is active and running
- ✅ Port 80 is listening on `0.0.0.0:80` (all interfaces)
- ✅ Server responds with HTTP 200 OK from localhost
- ✅ Files are deployed correctly
- ✅ Nginx configuration is valid

## Root Cause Analysis

Since the server is working correctly, the issue is **network connectivity** between your location and the server.

### Possible Causes

1. **Network Segmentation**
   - Your machine may not be on the `192.168.11.x` network
   - Different VLAN/subnet
   - Router configuration blocking inter-subnet traffic

2. **Proxmox Host Firewall**
   - Proxmox may have firewall rules blocking VM access
   - Container firewall enabled

3. **Router/Network Firewall**
   - Firewall rules blocking access to VMs
   - VLAN isolation
   - Network ACLs

4. **VM Firewall** (Fixed)
   - ✅ Disabled VM-level firewall
   - ✅ Updated nginx config to use `default_server`

## Solutions

### Option 1: Verify Network Connectivity

```bash
# Check if you can ping the server
ping 192.168.11.211

# Check if you're on the same network
ip addr show | grep "192.168.11"

# Test from a machine on the same network
curl -I http://192.168.11.211/
```

### Option 2: Access via Proxmox Host

If you're on the same network but can't access directly:

1. **SSH to Proxmox host first:**
   ```bash
   ssh root@192.168.11.10
   ```

2. **Then access from there:**
   ```bash
   curl -I http://192.168.11.211/
   ```

3. **Or set up SSH tunnel:**
   ```bash
   ssh -L 8080:192.168.11.211:80 root@192.168.11.10
   # Then access: http://localhost:8080/
   ```

### Option 3: Configure Proxmox Firewall

Check Proxmox firewall rules:

```bash
ssh root@192.168.11.10 "iptables -L -n -v"
ssh root@192.168.11.10 "pve-firewall status"
```

If firewall is blocking, allow traffic:

```bash
# Allow HTTP to VM
ssh root@192.168.11.10 "iptables -I INPUT -p tcp --dport 80 -s 192.168.11.0/24 -j ACCEPT"
```

### Option 4: Use NPMplus Proxy (Recommended)

Since you have NPMplus configured, use it instead:

1. **Configure NPMplus proxy host** (see `NPMPLUS_CONFIGURATION.md`):
   - Domain: `cross-all.defi-oracle.io`
   - Forward to: `http://192.168.11.211:80`
   - Enable SSL

2. **Access via domain:**
   ```
   https://cross-all.defi-oracle.io/
   ```

This is the recommended production approach anyway.

### Option 5: Check Router/Network Configuration

If you're on a different subnet:

1. **Check your IP:**
   ```bash
   ip addr show
   ```

2. **Check routing:**
   ```bash
   ip route show
   route -n | grep 192.168.11
   ```

3. **Check if router allows inter-subnet traffic**
   - Review router firewall rules
   - Check VLAN configuration
   - Verify routing tables

## Quick Fixes Applied

✅ **Updated nginx config** to use `default_server`:
```nginx
listen 80 default_server;
listen [::]:80 default_server;
```

✅ **Disabled VM firewall:**
```bash
pct set 2101 --net0 name=eth0,bridge=vmbr0,firewall=0
```

✅ **Removed default nginx site** that might interfere

## Verification

After applying fixes, verify:

```bash
# From the server itself
ssh root@192.168.11.10 "pct exec 2101 -- curl -I http://127.0.0.1/"

# From Proxmox host
ssh root@192.168.11.10 "curl -I http://192.168.11.211/"

# From your machine (if on same network)
curl -I http://192.168.11.211/
```

## Network Diagram

```
Your Machine → Router/Firewall → Proxmox Host (192.168.11.10) → VM (192.168.11.211)
     ?               ?                    ✅                      ✅
```

Each `?` is a potential point of failure.

## Recommended Solution

**Use NPMplus proxy** (already configured):
1. Access via domain: `https://cross-all.defi-oracle.io/`
2. Let NPMplus handle SSL/TLS termination
3. NPMplus is on the correct network and can reach the VM

This is the production-ready approach and avoids direct VM IP access issues.

---

**Last Updated**: 2025-01-22  
**Status**: Server OK, Network connectivity issue