Troubleshoot Cloudflare Tunnel Skill

Troubleshoot Cloudflare Tunnel Skill

Systematic diagnosis and resolution of Cloudflare Tunnel connectivity issues that prevent remote access to services.

Quick Start

Quick diagnostic for tunnel issues:

# Check cloudflared container status
docker ps | grep cloudflared

# Check recent tunnel registrations (should be within 10 minutes)
docker logs cloudflared --tail 100 | grep "Registered tunnel"

# Check for errors
docker logs cloudflared --tail 50 | grep -i error

# Restart if stuck
docker compose -f /​home/​dawiddutoit/​projects/​network/​docker-compose.yml restart cloudflared

Table of Contents

1. When to Use This Skill
2. What This Skill Does
3. Instructions
   • 3.1 Check Cloudflared Container Status
   • 3.2 Verify Tunnel Token Configuration
   • 3.3 Check Recent Tunnel Registrations
   • 3.4 Analyze Tunnel Logs for Errors
   • 3.5 Verify Tunnel in Cloudflare Dashboard
   • 3.6 Test Remote Access
   • 3.7 Apply Fix
4. Supporting Files
5. Expected Outcomes
6. Requirements
7. Red Flags to Avoid

When to Use This Skill

Explicit Triggers:

• "Tunnel not connecting"
• "Tunnel down"
• "Error 1033"
• "Remote access not working"
• "Fix Cloudflare Tunnel"
• "Cloudflared not working"

Implicit Triggers:

• Services work locally but not remotely
• Cloudflare dashboard shows tunnel as disconnected
• 502 Bad Gateway when accessing from internet
• Cloudflared container in restart loop

Debugging Triggers:

• "Why isn't remote access working?"
• "Why is tunnel disconnected?"
• "What is Error 1033?"

What This Skill Does

1. Checks Container - Verifies cloudflared container is running
2. Validates Token - Confirms CLOUDFLARE_TUNNEL_TOKEN is set
3. Checks Registrations - Verifies tunnel has registered recently (within 10 min)
4. Analyzes Logs - Searches for Error 1033, QUIC issues, connection failures
5. Checks Dashboard - Verifies tunnel status in Cloudflare Zero Trust
6. Tests Access - Attempts remote connection to verify tunnel routing
7. Provides Fix - Gives specific recovery commands

Instructions

3.1 Check Cloudflared Container Status

docker ps | grep cloudflared

Expected: Container status "Up" with uptime > 1 minute

Check container health:

docker inspect cloudflared --format='{{.State.Status}}: {{.State.Health.Status}}'

If not running or unhealthy:

# Check why it stopped
docker logs cloudflared --tail 100

# Restart
docker compose -f /​home/​dawiddutoit/​projects/​network/​docker-compose.yml up -d cloudflared

If in restart loop:

• Token likely invalid or missing
• Network connectivity issue
• Proceed to step 3.2

3.2 Verify Tunnel Token Configuration

Check token is set in environment:

docker exec cloudflared env | grep TUNNEL_TOKEN

Expected: Shows long base64-encoded token

If empty or missing:

1. Check .env file:

grep CLOUDFLARE_TUNNEL_TOKEN /​home/​dawiddutoit/​projects/​network/​.env

1. Verify docker-compose.yml passes it:

grep -A5 "cloudflared:" /​home/​dawiddutoit/​projects/​network/​docker-compose.yml | grep TUNNEL_TOKEN

1. Get new token from Cloudflare dashboard:

   • Go to: https://one.dash.cloudflare.com → Access → Tunnels
   • Click on tunnel → Configure
   • Copy token from command

2. Update .env and recreate container:

# Edit .env with new token
nano /​home/​dawiddutoit/​projects/​network/​.env

# Recreate container
docker compose -f /​home/​dawiddutoit/​projects/​network/​docker-compose.yml up -d --force-recreate cloudflared

3.3 Check Recent Tunnel Registrations

Healthy tunnel registers connections every few minutes:

# Check recent registrations (last 100 lines)
docker logs cloudflared --tail 100 | grep "Registered tunnel"

# Check timestamp of most recent registration
docker logs cloudflared --tail 100 | grep "Registered tunnel" | tail -1

Expected: Registration within last 10 minutes

If no recent registrations (older than 10 minutes):

• Tunnel is stuck or disconnected
• QUIC connection may have failed
• Network connectivity issue

Check QUIC connection health:

docker logs cloudflared --tail 100 | grep -i quic

3.4 Analyze Tunnel Logs for Errors

Search for common error patterns:

# Check for Error 1033 (tunnel disconnected)
docker logs cloudflared --tail 100 | grep "1033"

# Check for general errors
docker logs cloudflared --tail 100 | grep -i error

# Check for authentication issues
docker logs cloudflared --tail 100 | grep -i "auth\|unauthorized\|forbidden"

# Check for network issues
docker logs cloudflared --tail 100 | grep -i "connect\|timeout\|dial"

Common error patterns:

3.5 Verify Tunnel in Cloudflare Dashboard

Check tunnel status in Cloudflare Zero Trust:

1. Go to: https://one.dash.cloudflare.com
2. Navigate to: Access → Tunnels
3. Find your tunnel in list

Expected status: "Healthy" with green indicator

If "Down" or "Unhealthy":

• Tunnel not connected from server side
• Proceed to restart (step 3.7)

Check tunnel routes:

1. Click tunnel name → Configure
2. Verify Public Hostname routes are configured
3. Expected routes:
   • pihole.temet.ai → https://caddy:443
   • ha.temet.ai → https://caddy:443
   • jaeger.temet.ai → https://caddy:443
   • etc.

3.6 Test Remote Access

Test accessing a service from internet (not local WiFi):

From mobile (using cellular data, not WiFi):

https://pihole.temet.ai

Expected: Cloudflare Access login page appears (or service if already authenticated)

Alternatively, use external proxy:

# Test from external service
curl -I --connect-timeout 10 https://pihole.temet.ai

If connection fails:

• 502 Bad Gateway → Tunnel not routing correctly
• Timeout → Tunnel not connected
• Connection refused → Cloudflared not running
• SSL error → Certificate issue (different skill)

3.7 Apply Fix

Fix A: Stuck Tunnel (most common)

Restart cloudflared container:

docker compose -f /​home/​dawiddutoit/​projects/​network/​docker-compose.yml restart cloudflared

Wait 30 seconds, then verify:

docker logs cloudflared --tail 20 | grep "Registered tunnel"

Expected: Fresh registrations appearing

Fix B: Invalid Token

Get new token and recreate container:

# 1. Get new token from dashboard:
#    https://one.dash.cloudflare.com → Access → Tunnels → Configure

# 2. Update .env
nano /​home/​dawiddutoit/​projects/​network/​.env
# Add: CLOUDFLARE_TUNNEL_TOKEN="new-token-here"

# 3. Recreate container
docker compose -f /​home/​dawiddutoit/​projects/​network/​docker-compose.yml up -d --force-recreate cloudflared

# 4. Verify
docker logs cloudflared --tail 20

Fix C: Network Connectivity Issue

Check internet connectivity:

# Test connectivity to Cloudflare
docker exec cloudflared ping -c 3 1.1.1.1

# Test DNS resolution
docker exec cloudflared nslookup cloudflare.com

# Check container network
docker network inspect network_default

If network issues found, may need to recreate Docker network (see Docker network troubleshooting).

Fix D: Complete Tunnel Reset

If all else fails, full reset:

# Stop all services
cd /​home/​dawiddutoit/​projects/​network && \
docker compose down

# Recreate network
docker network rm network_default
docker network create network_default

# Start services
docker compose up -d

# Monitor tunnel connection
docker logs cloudflared -f

Watch for "Registered tunnel" messages appearing.

Supporting Files

Expected Outcomes

Success:

• Cloudflared container running and healthy
• Recent tunnel registrations (within 10 minutes)
• Tunnel shows "Healthy" in Cloudflare dashboard
• Remote access works with OAuth prompt
• No Error 1033 in logs

Partial Success:

• Tunnel connecting but routes not configured (add routes in dashboard)
• Tunnel working but intermittent (network instability)

Failure Indicators:

• Cloudflared container not running or restarting
• No tunnel registrations in logs
• Error 1033 persists after restart
• Remote access returns 502 Bad Gateway

Requirements

• Docker running with cloudflared container
• Valid Cloudflare Tunnel token
• Internet connectivity from server
• Cloudflare Zero Trust account
• Tunnel configured in Cloudflare dashboard

Red Flags to Avoid

• Do not delete tunnel in Cloudflare dashboard (creates orphaned token)
• Do not expose ports 80/​443 if tunnel not working (security risk)
• Do not skip checking logs before restart (miss root cause)
• Do not restart tunnel repeatedly (causes rate limiting)
• Do not test remote access from local WiFi (use cellular/​external)
• Do not confuse tunnel token with API token (different credentials)
• Do not modify tunnel routes without updating Caddyfile

Notes

• Tunnel registrations should occur every few minutes (QUIC keep-alive)
• Error 1033 typically indicates stuck/​stale tunnel process
• Tunnel uses outbound QUIC connection (no inbound ports needed)
• Maximum tunnel downtime before auto-disconnect: ~10 minutes
• Automated monitoring (infrastructure-monitor.sh) detects stuck tunnels
• Tunnel routes are configured in Cloudflare dashboard, not locally
• Use infrastructure-health-check skill for comprehensive diagnostics