OPNsense (Docker Proxy)

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Proxy to OPNsense API for monitoring.

Overview

NGINX is a high-performance web server and reverse proxy server originally developed by Igor Sysoev in 2004 to solve the C10K problem of handling ten thousand concurrent connections. Its event-driven, asynchronous architecture makes it exceptionally efficient at handling multiple connections with minimal resource consumption, establishing it as the backbone of many high-traffic websites and critical infrastructure components worldwide. This OPNsense proxy configuration leverages NGINX's reverse proxy capabilities to create a secure intermediary layer between external monitoring tools and your OPNsense firewall's API endpoints. OPNsense, being a FreeBSD-based firewall solution, exposes REST API endpoints for system monitoring and configuration, but direct access often requires complex authentication handling and poses security concerns. NGINX acts as an intelligent proxy, handling authentication, request routing, and connection management while providing additional layers of security through rate limiting and access controls. Network administrators and homelab enthusiasts managing OPNsense firewalls will find this proxy invaluable for integrating firewall metrics into monitoring dashboards like Grafana, centralized logging systems, or custom automation scripts. The proxy eliminates the complexity of handling OPNsense's API authentication in multiple applications while providing a standardized HTTP interface that monitoring tools can easily consume, making firewall observability significantly more accessible.

Key Features

Event-driven asynchronous architecture handling thousands of concurrent API connections with minimal memory overhead
Advanced upstream health checking and automatic failover for OPNsense API endpoint availability
Built-in rate limiting and connection throttling to protect OPNsense from API abuse
SSL/TLS termination with configurable cipher suites for encrypted API communications
Request buffering and response caching to reduce load on OPNsense hardware
Detailed access logging with customizable log formats for API usage analytics
WebSocket proxying support for real-time OPNsense monitoring applications
Geographic and IP-based access controls for API security hardening

Common Use Cases

1Grafana dashboard integration for real-time OPNsense firewall metrics and performance monitoring
2Centralized SIEM integration collecting OPNsense logs and security events through API endpoints
3Multi-tenant environments where different teams need controlled access to specific OPNsense API functions
4Homelab monitoring stacks requiring consolidated network device metrics alongside server infrastructure
5Automated network configuration management systems updating OPNsense rules and policies via API
6Load balancing API requests across multiple OPNsense instances in high-availability setups
7Development environments testing OPNsense integrations without exposing production firewall APIs

Prerequisites

OPNsense firewall with API access enabled in System > Access > Users configuration panel
Valid OPNsense API key and secret pair generated for authentication to API endpoints
Minimum 256MB RAM allocated to NGINX container for optimal proxy performance under load
Network connectivity between Docker host and OPNsense management interface on required ports
Understanding of NGINX configuration syntax for customizing proxy behaviors and security policies
Port 8080 available on Docker host for external access to the OPNsense proxy service

For development & testing. Review security settings, change default credentials, and test thoroughly before production use. See Terms

docker-compose.yml

1services: 
2  opnsense-proxy: 
3    image: nginx:alpine
4    container_name: opnsense-proxy
5    restart: unless-stopped
6    volumes: 
7      - ./nginx.conf:/etc/nginx/nginx.conf:ro
8    ports: 
9      - "8080:80"

.env Template

.env

1# Configure nginx.conf for OPNsense API

Usage Notes

1Docs: https://docs.opnsense.org/development/api.html
2Configure nginx.conf to proxy requests to OPNsense API
3Enable API access in OPNsense: System > Access > Users
4Create API key+secret for authentication
5Use for Grafana dashboards, monitoring integrations
6OPNsense itself runs on dedicated hardware, not Docker

Quick Start

terminal

1# 1. Create the compose file
2cat > docker-compose.yml << 'EOF'
3services:
4  opnsense-proxy:
5    image: nginx:alpine
6    container_name: opnsense-proxy
7    restart: unless-stopped
8    volumes:
9      - ./nginx.conf:/etc/nginx/nginx.conf:ro
10    ports:
11      - "8080:80"
12EOF
13
14# 2. Create the .env file
15cat > .env << 'EOF'
16# Configure nginx.conf for OPNsense API
17EOF
18
19# 3. Start the services
20docker compose up -d
21
22# 4. View logs
23docker compose logs -f

One-Liner

Run this command to download and set up the recipe in one step:

terminal

1curl -fsSL https://docker.recipes/api/recipes/opnsense/run | bash

Troubleshooting

502 Bad Gateway errors: Verify OPNsense management interface is accessible and API endpoints are responding correctly
Authentication failures in proxy logs: Check OPNsense API key/secret configuration and ensure they're properly encoded in NGINX upstream directives
High memory usage in NGINX container: Reduce proxy_buffering settings or increase worker_rlimit_nofile for better connection handling
SSL certificate errors when connecting to OPNsense: Configure proxy_ssl_verify off in NGINX upstream block for self-signed certificates
Rate limiting blocking legitimate requests: Adjust limit_req_zone parameters in NGINX configuration to match expected API usage patterns
Container fails to start with permission denied: Ensure nginx.conf file has proper read permissions and valid syntax using nginx -t command

Community Notes

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