Cloudflare Setup Guide

Configure Cloudflare as a DNS provider and CDN/proxy for the NoETL Gateway.

Overview

Cloudflare provides:

• DNS Management: Manage DNS records for your domain
• CDN/Proxy: Cache and protect your gateway
• SSL/TLS: Free SSL certificates
• DDoS Protection: Protect against attacks
• WAF: Web Application Firewall rules

Prerequisites

• Domain registered and nameservers pointed to Cloudflare
• NoETL Gateway deployed with a static IP address
• Cloudflare account (free tier is sufficient)

Current Production Configuration

:::info NoETL Gateway (mestumre.dev)

Setting	Value
Domain	mestumre.dev
Subdomain	gateway.mestumre.dev
Static IP	34.46.180.136
SSL Mode	Flexible
:::

DNS Configuration

Add A Record for Gateway

1. Log into Cloudflare Dashboard
2. Select your domain (e.g., mestumre.dev)
3. Go to DNS > Records
4. Click Add record (or Edit existing)
5. Configure:

Field	Value
Type	A
Name	gateway
IPv4 address	34.46.180.136
Proxy status	Proxied (orange cloud)
TTL	Auto

6. Click Save

DNS Propagation

DNS changes typically propagate within minutes when using Cloudflare. Verify:

# Check DNS resolution
dig gateway.mestumre.dev

# Should return Cloudflare proxy IPs (not your static IP - that's expected when proxied)
nslookup gateway.mestumre.dev

SSL/TLS Configuration

Encryption Mode

1. Go to SSL/TLS > Overview
2. Select encryption mode:

Mode	Description	When to Use
Off	No encryption	Never (insecure)
Flexible	HTTPS to Cloudflare, HTTP to origin	LoadBalancer without TLS (current setup)
Full	HTTPS to origin (self-signed OK)	Origin has any certificate
Full (strict)	HTTPS to origin (valid cert required)	Origin has valid certificate

Recommended for NoETL Gateway: Use Flexible when using a LoadBalancer service without TLS termination (HTTP on port 80). Use Full or Full (strict) if using GKE Ingress with managed certificates.

Edge Certificates

Cloudflare automatically provisions SSL certificates for proxied domains. Verify:

1. Go to SSL/TLS > Edge Certificates
2. Ensure "Universal SSL" is active
3. Check certificate covers gateway.yourdomain.com

Always Use HTTPS

1. Go to SSL/TLS > Edge Certificates
2. Enable Always Use HTTPS

This redirects all HTTP requests to HTTPS.

Caching Configuration

API and OPTIONS Caching (Disable) - Required for CORS

API endpoints and OPTIONS preflight requests must not be cached. Create a Cache Rule:

1. Go to Caching > Cache Rules
2. Click Create rule
3. Configure:
   • Rule name: Bypass API and OPTIONS
   • When incoming requests match (use "Edit expression"):

     (http.request.uri.path contains "/api") or (http.request.method eq "OPTIONS")

   • Then: Bypass cache
4. Click Deploy

:::warning Important for CORS This rule is critical for CORS to work. Without it, Cloudflare may cache OPTIONS preflight responses without the required CORS headers, causing authentication to fail. :::

Static Assets (Optional)

If serving static files through gateway, enable caching:

1. Create another Cache Rule
2. Match: URI Path ends with .js, .css, .html
3. Then: Cache with TTL

Security Configuration

Firewall Rules

Block Bad Bots

1. Go to Security > WAF > Custom rules
2. Create rule:
   • Name: Block bad bots
   • Expression: (cf.client.bot)
   • Action: Block

Rate Limiting

1. Go to Security > WAF > Rate limiting rules
2. Create rule:
   • Name: API rate limit
   • Expression: (http.request.uri.path contains "/api/")
   • Requests: 100 per 10 seconds
   • Action: Block

DDoS Protection

DDoS protection is automatically enabled. Adjust sensitivity:

1. Go to Security > DDoS
2. Review L7 DDoS settings
3. Adjust if needed (default usually fine)

CORS Considerations

Cloudflare and CORS

When Cloudflare proxies requests:

• CORS headers from origin are passed through
• Cloudflare doesn't add or remove CORS headers by default

Preflight Caching Issue

If CORS preflight (OPTIONS) requests fail after working initially:

Cause: Cloudflare may cache the preflight response without CORS headers

Solution: Create a Cache Rule to bypass OPTIONS requests:

1. Go to Caching > Cache Rules
2. Create rule:
   • Name: Bypass OPTIONS cache
   • Expression: (http.request.method eq "OPTIONS")
   • Then: Bypass cache
3. Deploy

Gateway CORS Configuration

Ensure gateway allows Cloudflare-proxied requests. Current configuration:

# automation/helm/gateway/values.yaml
env:
  corsAllowedOrigins: "http://localhost:8080,http://localhost:8090,http://localhost:3000,https://gateway.mestumre.dev"

This allows:

• Local development on ports 8080, 8090, 3000
• Production requests via https://gateway.mestumre.dev

Page Rules (Legacy)

For fine-grained control, use Page Rules:

Bypass Cache for API

1. Go to Rules > Page Rules
2. Create rule:
   • URL: gateway.yourdomain.com/api/*
   • Setting: Cache Level = Bypass

Security Level for API

1. Create rule:
   • URL: gateway.yourdomain.com/api/*
   • Setting: Security Level = High

Monitoring

Analytics

1. Go to Analytics > Traffic
2. Monitor:
   • Total requests
   • Cached vs uncached
   • Threats blocked
   • Response codes

Logs (Enterprise)

Enterprise plans can stream logs to external services:

1. Go to Analytics > Logs
2. Configure log destination

Health Checks (Pro+)

1. Go to Traffic > Health Checks
2. Create check:
   • Name: Gateway health
   • Address: gateway.yourdomain.com
   • Path: /health
   • Interval: 60 seconds

Troubleshooting

DNS Not Resolving

# Check Cloudflare nameservers
dig NS yourdomain.com

# Should show Cloudflare nameservers
# Example: xxx.ns.cloudflare.com

SSL Certificate Errors

Error: "Invalid SSL certificate"

Solutions:

1. Wait for certificate provisioning (up to 24 hours)
2. Check domain is active in Cloudflare
3. Verify SSL mode matches your origin setup

Gateway Unreachable

Error: "Error 521 - Web server is down"

Cause: Cloudflare can't reach your origin

Solutions:

1. Verify gateway LoadBalancer has external IP
2. Check gateway health: curl http://YOUR_STATIC_IP/health
3. Verify firewall rules allow Cloudflare IPs

Cloudflare IP Ranges

Allow Cloudflare IPs in your firewall:

# Get current Cloudflare IP ranges
curl https://www.cloudflare.com/ips-v4
curl https://www.cloudflare.com/ips-v6

"Error 522 - Connection Timed Out"

Cause: Origin is slow to respond

Solutions:

1. Check gateway pod health
2. Increase gateway resources
3. Check network policies in GKE

"Error 524 - A Timeout Occurred"

Cause: Request takes too long (>100s)

Solutions:

1. Optimize slow API endpoints
2. Consider async processing for long operations
3. Enterprise: Increase timeout limits

Best Practices

Security

• Enable "Always Use HTTPS"
• Set SSL mode to "Full (strict)" when possible
• Enable bot protection
• Configure rate limiting

Performance

• Use caching rules appropriately
• Enable Brotli compression (Settings > Speed > Optimization)
• Consider Argo Smart Routing (paid feature)

Reliability

• Set up health checks (Pro+)
• Configure load balancing if multiple origins
• Enable origin error page customization

Quick Reference

DNS Record (mestumre.dev)

Type	Name	Content	Proxy	TTL
A	gateway	34.46.180.136	Proxied	Auto
A	@	35.226.162.30	Proxied	Auto

Apex Conflict Note

Cloudflare cannot keep both of these at the same time for mestumre.dev:

• CNAME @ -> c.storage.googleapis.com
• A @ -> 35.226.162.30

If you want GUI on https://mestumre.dev, remove the existing apex CNAME and use the apex A record above. If you must keep the apex CNAME, use gui.mestumre.dev for GUI and point that subdomain to 35.226.162.30.

Required Settings

Setting	Location	Value
SSL Mode	SSL/TLS > Overview	Flexible (for HTTP LoadBalancer)
Always HTTPS	SSL/TLS > Edge Certificates	On
Cache Bypass	Caching > Cache Rules	(http.request.uri.path contains "/api") or (http.request.method eq "OPTIONS")

Verification Commands

# Test DNS
dig gateway.mestumre.dev

# Test health endpoint
curl https://gateway.mestumre.dev/health

# Test CORS preflight
curl -I -X OPTIONS https://gateway.mestumre.dev/api/auth/login \
  -H "Origin: http://localhost:8090" \
  -H "Access-Control-Request-Method: POST"