# VMID 2400 - DNS CNAME Structure

**Last Updated:** 2026-01-31  
**Document Version:** 1.0  
**Status:** Active Documentation

---

**Date**: 2026-01-02  
**Domain**: `defi-oracle.io`  
**Purpose**: Two-level CNAME structure for ThirdWeb RPC endpoint

---

## DNS Structure

The DNS configuration uses a two-level CNAME chain for flexibility:

```
rpc.defi-oracle.io
    ↓ (CNAME)
rpc.public-0138.defi-oracle.io
    ↓ (CNAME)
26138c21-db00-4a02-95db-ec75c07bda5b.cfargotunnel.com
    ↓ (Cloudflare Tunnel)
192.168.11.240:443 (Nginx) → 127.0.0.1:8545 (Besu RPC)
```

---

## DNS Records to Create

### Record 1: Tunnel Endpoint

```
Type: CNAME
Name: rpc.public-0138
Domain: defi-oracle.io
Target: 26138c21-db00-4a02-95db-ec75c07bda5b.cfargotunnel.com
Proxy: 🟠 Proxied (orange cloud)
TTL: Auto
```

**Full FQDN**: `rpc.public-0138.defi-oracle.io`  
**Purpose**: Points directly to the Cloudflare tunnel endpoint

---

### Record 2: Short Alias

```
Type: CNAME
Name: rpc
Domain: defi-oracle.io
Target: rpc.public-0138.defi-oracle.io
Proxy: 🟠 Proxied (orange cloud)
TTL: Auto
```

**Full FQDN**: `rpc.defi-oracle.io`  
**Purpose**: Provides a shorter, more convenient alias that resolves to the full FQDN

---

## Benefits of Two-Level Structure

1. **Flexibility**: Can change the tunnel endpoint without updating the short alias
2. **Convenience**: `rpc.defi-oracle.io` is easier to remember and use
3. **Backwards Compatibility**: If you need to change the tunnel or endpoint structure, only the first CNAME needs updating
4. **Organization**: The `rpc.public-0138` name clearly indicates it's for ChainID 138 public RPC

---

## Usage

Both endpoints will work and resolve to the same tunnel:

**Full FQDN**:
- `https://rpc.public-0138.defi-oracle.io`

**Short Alias**:
- `https://rpc.defi-oracle.io`

Both URLs will:
1. Resolve through the CNAME chain
2. Connect to Cloudflare tunnel `26138c21-db00-4a02-95db-ec75c07bda5b`
3. Route to VMID 2400 (192.168.11.240)
4. Be handled by Nginx on port 443
5. Proxy to Besu RPC on port 8545

---

## Cloudflare Dashboard Configuration

### Step 1: Create First CNAME (Tunnel Endpoint)

1. Go to: **DNS** → **Records**
2. Click: **Add record**
3. Configure:
   - **Type**: CNAME
   - **Name**: `rpc.public-0138`
   - **Target**: `26138c21-db00-4a02-95db-ec75c07bda5b.cfargotunnel.com`
   - **Proxy**: 🟠 Proxied
   - **TTL**: Auto
4. Click: **Save**

### Step 2: Create Second CNAME (Short Alias)

1. Click: **Add record** again
2. Configure:
   - **Type**: CNAME
   - **Name**: `rpc`
   - **Target**: `rpc.public-0138.defi-oracle.io`
   - **Proxy**: 🟠 Proxied
   - **TTL**: Auto
3. Click: **Save**

---

## Verification

### Test DNS Resolution

```bash
# Test full FQDN
dig rpc.public-0138.defi-oracle.io
nslookup rpc.public-0138.defi-oracle.io

# Test short alias
dig rpc.defi-oracle.io
nslookup rpc.defi-oracle.io

# Both should resolve to Cloudflare IPs (if proxied)
```

### Test Endpoints

```bash
# Test full FQDN
curl -k https://rpc.public-0138.defi-oracle.io/health

# Test short alias
curl -k https://rpc.defi-oracle.io/health

# Both should work identically
```

---

## Important Notes

1. **Proxy Status**: Both CNAME records should be **Proxied** (🟠 orange cloud) for DDoS protection and SSL termination

2. **CNAME Chain**: Cloudflare supports CNAME chains, so `rpc` → `rpc.public-0138` → `tunnel` works correctly

3. **Tunnel Route**: The tunnel route in Cloudflare should be configured for `rpc.public-0138.defi-oracle.io` (the actual endpoint), but both URLs will work since DNS resolves the short alias first

4. **Nginx Configuration**: Nginx is configured for `rpc.public-0138.defi-oracle.io` as the server_name. If you want to support both, you can add `rpc.defi-oracle.io` to the server_name directive, but it's not required since Cloudflare handles the DNS resolution.

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## Troubleshooting

### CNAME Chain Not Resolving

- Wait 1-2 minutes for DNS propagation
- Verify both CNAME records are created correctly
- Check that the target of the first CNAME (`rpc.public-0138`) points to the tunnel endpoint
- Verify tunnel is healthy in Cloudflare Dashboard

### Only One URL Works

- Check that both CNAME records are created
- Verify both are set to Proxied (orange cloud)
- Test DNS resolution for both: `dig rpc.defi-oracle.io` and `dig rpc.public-0138.defi-oracle.io`

---

**Last Updated**: 2026-01-02  
**Status**: ✅ **DOCUMENTATION COMPLETE**