Agent reads logs and detects attack patterns (scenarios) Decisions are created: ban IP, show captcha, throttle Bouncers enforce decisions at the reverse proxy, firewall, or CDN level Community: your detections contribute to the global blocklist; you receive others' detections ---

How to Self-Host CrowdSec 2026

TL;DR

CrowdSec (MIT, ~10K GitHub stars, Go) is a collaborative intrusion detection and prevention system. Like fail2ban, it detects attacks by reading logs — but then shares threat intelligence with the entire CrowdSec network, so everyone benefits. It automatically blocks known bad IPs using community-contributed blocklists. Cloudflare WAF costs $20/month for basic protection. CrowdSec gives you crowd-sourced threat intelligence for free.

Key Takeaways

CrowdSec: MIT, ~10K stars, Go — modern collaborative IDS/IPS
Crowd-sourced blocklists: Block IPs that are attacking other CrowdSec users worldwide
Bouncers: Enforcement components for Caddy, Nginx, iptables, Cloudflare, and more
Scenarios: Detect brute force, credential stuffing, port scanning, L7 DDoS
Console: Free web dashboard at app.crowdsec.net for monitoring
vs fail2ban: CrowdSec adds shared threat intelligence and a richer scenario system

How CrowdSec Works

Logs (Nginx, SSH, etc.)  →  CrowdSec Agent  →  Decisions (ban, captcha)
                              ↑ ↓                    ↓
                         CrowdSec API        Bouncers (enforce)
                              ↑ ↓
                       Community Intel
                    (crowd-sourced blocklists)

Agent reads logs and detects attack patterns (scenarios)
Decisions are created: ban IP, show captcha, throttle
Bouncers enforce decisions at the reverse proxy, firewall, or CDN level
Community: your detections contribute to the global blocklist; you receive others' detections

CrowdSec vs fail2ban

Feature	CrowdSec	fail2ban
Shared threat intel	Yes (crowd-sourced)	No (local only)
IP reputation lists	Yes (community)	No
Language	Go	Python
Performance	Fast	Slow with many rules
Actions	Ban, captcha, throttle	Ban only
Web console	Yes (free)	No
API	REST API	CLI only
Bouncer ecosystem	Rich (Caddy, Nginx, CF)	iptables only
Configuration	YAML scenarios	Regex filters

Part 1: Docker Setup

# docker-compose.yml
services:
  crowdsec:
    image: crowdsecurity/crowdsec:latest
    container_name: crowdsec
    restart: unless-stopped
    ports:
      - "8080:8080"    # API (local only — don't expose publicly)
      - "6060:6060"    # Prometheus metrics (optional)
    volumes:
      # CrowdSec config and data:
      - crowdsec_config:/etc/crowdsec
      - crowdsec_data:/var/lib/crowdsec/data

      # Log sources (mount the logs you want CrowdSec to watch):
      - /var/log:/var/log:ro
      - caddy_logs:/var/log/caddy:ro           # Caddy access logs
      # - nginx_logs:/var/log/nginx:ro          # Nginx logs
      # - /var/log/auth.log:/var/log/auth.log:ro  # SSH logs

    environment:
      # Collections to install on first run:
      COLLECTIONS: >-
        crowdsecurity/linux
        crowdsecurity/caddy
        crowdsecurity/http-cve
        crowdsecurity/whitelist-good-actors
      # crowdsecurity/nginx            # If using Nginx
      # crowdsecurity/sshd             # If SSH is exposed

      # Enroll in CrowdSec Console (optional):
      # ENROLL_KEY: "your-enrollment-key"
      # ENROLL_INSTANCE_NAME: "my-server"

volumes:
  crowdsec_config:
  crowdsec_data:
  caddy_logs:        # Your Caddy log volume

docker compose up -d

# Check it's running:
docker exec crowdsec cscli version
docker exec crowdsec cscli metrics

Part 2: Configure Log Sources

Caddy

Make sure Caddy logs to a file that CrowdSec can read:

{
    log {
        output file /var/log/caddy/access.log
        format json
    }
}

CrowdSec acquirer config:

# /etc/crowdsec/acquis.yaml (or acquis.d/caddy.yaml)
source: file
filenames:
  - /var/log/caddy/access.log
labels:
  type: caddy

Nginx

source: file
filenames:
  - /var/log/nginx/access.log
  - /var/log/nginx/error.log
labels:
  type: nginx

SSH

source: file
filenames:
  - /var/log/auth.log
labels:
  type: syslog

Docker container logs

source: docker
container_name:
  - my-webapp
labels:
  type: nginx

Part 3: Install Bouncers

Bouncers enforce CrowdSec's decisions (bans, captchas, etc.).

Caddy Bouncer

# Generate an API key for the bouncer:
docker exec crowdsec cscli bouncers add caddy-bouncer
# Outputs: API key = abc123...

# Add to docker-compose.yml:
  caddy:
    image: caddy:latest
    # Use the CrowdSec Caddy module:
    # Build a custom Caddy with: xcaddy build --with github.com/hslatman/caddy-crowdsec-bouncer
    volumes:
      - ./Caddyfile:/etc/caddy/Caddyfile

{
    crowdsec {
        api_url http://crowdsec:8080
        api_key abc123...
        ticker_interval 15s
    }
}

yourdomain.com {
    crowdsec
    reverse_proxy localhost:3000
}

Nginx Bouncer

# Generate bouncer API key:
docker exec crowdsec cscli bouncers add nginx-bouncer

# docker-compose.yml:
  nginx-bouncer:
    image: crowdsecurity/cs-openresty-bouncer:latest
    container_name: nginx-bouncer
    restart: unless-stopped
    environment:
      CROWDSEC_BOUNCER_API_KEY: "abc123..."
      CROWDSEC_AGENT_HOST: "crowdsec:8080"
    depends_on:
      - crowdsec

Firewall Bouncer (iptables/nftables)

# Install directly on the host:
curl -s https://install.crowdsec.net | sudo bash
sudo apt install crowdsec-firewall-bouncer-iptables

# Or nftables:
sudo apt install crowdsec-firewall-bouncer-nftables

# Configure:
sudo vim /etc/crowdsec/bouncers/crowdsec-firewall-bouncer.yaml
# api_url: http://localhost:8080
# api_key: abc123...

Cloudflare Bouncer

docker exec crowdsec cscli bouncers add cloudflare-bouncer

# docker-compose.yml:
  cloudflare-bouncer:
    image: crowdsecurity/cs-cloudflare-bouncer:latest
    restart: unless-stopped
    environment:
      CROWDSEC_BOUNCER_API_KEY: "abc123..."
      CROWDSEC_AGENT_HOST: "crowdsec:8080"
      CLOUDFLARE_API_TOKEN: "${CF_API_TOKEN}"
      CLOUDFLARE_ACCOUNT_ID: "${CF_ACCOUNT_ID}"

Part 4: Scenarios and Collections

List installed scenarios

docker exec crowdsec cscli scenarios list
docker exec crowdsec cscli collections list

Install additional collections

# WordPress protection:
docker exec crowdsec cscli collections install crowdsecurity/wordpress

# Traefik:
docker exec crowdsec cscli collections install crowdsecurity/traefik

# HTTP generic attacks:
docker exec crowdsec cscli collections install crowdsecurity/http-cve

# Whitelist known good bots (Google, Bing, etc.):
docker exec crowdsec cscli collections install crowdsecurity/whitelist-good-actors

What scenarios detect

Scenario	Detects
`crowdsecurity/http-bf`	HTTP brute force (login pages)
`crowdsecurity/ssh-bf`	SSH brute force
`crowdsecurity/http-crawl-non_statics`	Aggressive crawlers
`crowdsecurity/http-bad-user-agent`	Known malicious user agents
`crowdsecurity/http-path-traversal`	Path traversal attempts
`crowdsecurity/http-sqli`	SQL injection attempts
`crowdsecurity/http-xss`	Cross-site scripting attempts
`crowdsecurity/http-cve-*`	Known CVE exploits

Part 5: Managing Decisions

# View active decisions (bans):
docker exec crowdsec cscli decisions list

# Ban an IP manually:
docker exec crowdsec cscli decisions add -i 1.2.3.4 -d 24h -t ban -r "manual block"

# Ban a range:
docker exec crowdsec cscli decisions add -r 1.2.3.0/24 -d 48h -t ban -r "abusive range"

# Remove a ban:
docker exec crowdsec cscli decisions delete -i 1.2.3.4

# Whitelist your own IP:
cat >> /etc/crowdsec/parsers/s02-enrich/whitelist.yaml << 'EOF'
name: my-whitelist
description: "Whitelist my IPs"
whitelist:
  reason: "My trusted IPs"
  ip:
    - "203.0.113.10"    # Your home IP
    - "10.0.0.0/8"      # Internal network
EOF
docker exec crowdsec cscli hub update
docker compose restart crowdsec

Part 6: CrowdSec Console

The free cloud console at app.crowdsec.net provides:

Real-time alert visualization
Attack statistics and trends
Community blocklist status
Multi-instance management

Enroll your instance

# Get enrollment key from app.crowdsec.net:
docker exec crowdsec cscli console enroll YOUR_ENROLLMENT_KEY \
  --name "my-server" \
  --tags "production,web"

Part 7: Alerts and Notifications

Send alerts to ntfy

# /etc/crowdsec/notifications/ntfy.yaml
type: http
name: ntfy
log_level: info
format: |
  {{ range . -}}
  {{ .Alert.Scenario }} triggered by {{ .Alert.Source.IP }}
  {{ end -}}

url: "https://ntfy.yourdomain.com/crowdsec-alerts"
method: POST
headers:
  Title: "CrowdSec Alert"
  Priority: "high"
  Tags: "shield"

# /etc/crowdsec/profiles.yaml (add notification):
name: default_ip_remediation
filters:
  - Alert.Remediation == true && Alert.GetScope() == "Ip"
decisions:
  - type: ban
    duration: 4h
notifications:
  - ntfy
on_success: break

Part 8: Metrics and Monitoring

# View metrics:
docker exec crowdsec cscli metrics

# Sample output:
# Acquisition:
#   /var/log/caddy/access.log: 15423 lines read, 12 events parsed
# Parsers:
#   crowdsecurity/caddy-logs: 12 parsed
# Scenarios:
#   crowdsecurity/http-bf: 3 triggered

# View alert history:
docker exec crowdsec cscli alerts list

# View specific alert:
docker exec crowdsec cscli alerts inspect 42

# Prometheus metrics (if port 6060 exposed):
curl localhost:6060/metrics

Maintenance

# Update:
docker compose pull
docker compose up -d

# Update hub (scenarios, parsers, collections):
docker exec crowdsec cscli hub update
docker exec crowdsec cscli hub upgrade

# Backup config:
tar -czf crowdsec-config-$(date +%Y%m%d).tar.gz \
  $(docker volume inspect crowdsec_crowdsec_config --format '{{.Mountpoint}}')

# Check bouncer connectivity:
docker exec crowdsec cscli bouncers list

# Logs:
docker compose logs -f crowdsec

Why Self-Host CrowdSec?

The case for self-hosting CrowdSec comes down to three practical factors: data ownership, cost at scale, and operational control.

Data ownership is the fundamental argument. When you use a SaaS version of any tool, your data lives on someone else's infrastructure subject to their terms of service, their security practices, and their business continuity. If the vendor raises prices, gets acquired, changes API limits, or shuts down, you're left scrambling. Self-hosting CrowdSec means your data and configuration stay on infrastructure you control — whether that's a VPS, a bare metal server, or a home lab.

Cost at scale matters once you move beyond individual use. Most SaaS equivalents charge per user or per data volume. A self-hosted instance on a $10-20/month VPS typically costs less than per-user SaaS pricing for teams of five or more — and the cost doesn't scale linearly with usage. One well-configured server handles dozens of users for a flat monthly fee.

Operational control is the third factor. The Docker Compose configuration above exposes every setting that commercial equivalents often hide behind enterprise plans: custom networking, environment variables, storage backends, and authentication integrations. You decide when to update, how to configure backups, and what access controls to apply.

The honest tradeoff: you're responsible for updates, backups, and availability. For teams running any production workloads, this is familiar territory. For individuals, the learning curve is real but the tooling (Docker, Caddy, automated backups) is well-documented and widely supported.

Server Requirements and Sizing

Before deploying CrowdSec, assess your server capacity against expected workload.

Minimum viable setup: A 1 vCPU, 1GB RAM VPS with 20GB SSD is sufficient for personal use or small teams. Most consumer VPS providers — Hetzner, DigitalOcean, Linode, Vultr — offer machines in this range for $5-10/month. Hetzner offers excellent price-to-performance for European and US regions.

Recommended production setup: 2 vCPUs with 4GB RAM and 40GB SSD handles most medium deployments without resource contention. This gives CrowdSec headroom for background tasks, caching, and concurrent users while leaving capacity for other services on the same host.

Storage planning: The Docker volumes in this docker-compose.yml store all persistent CrowdSec data. Estimate your storage growth rate early — for data-intensive tools, budget for 3-5x your initial estimate. Hetzner Cloud and Vultr both support online volume resizing without stopping your instance.

Operating system: Any modern 64-bit Linux distribution works. Ubuntu 22.04 LTS and Debian 12 are the most commonly tested configurations. Ensure Docker Engine 24.0+ and Docker Compose v2 are installed — verify with docker --version and docker compose version. Avoid Docker Desktop on production Linux servers; it adds virtualization overhead and behaves differently from Docker Engine in ways that cause subtle networking issues.

Network: Only ports 80 and 443 need to be publicly accessible when running behind a reverse proxy. Internal service ports should be bound to localhost only. A minimal UFW firewall that blocks all inbound traffic except SSH, HTTP, and HTTPS is the single most effective security measure for a self-hosted server.

Backup and Disaster Recovery

Running CrowdSec without a tested backup strategy is an unacceptable availability risk. Docker volumes are not automatically backed up — if you delete a volume or the host fails, data is gone with no recovery path.

What to back up: The named Docker volumes containing CrowdSec's data (database files, user uploads, application state), your docker-compose.yml and any customized configuration files, and .env files containing secrets.

Backup approach: For simple setups, stop the container, archive the volume contents, then restart. For production environments where stopping causes disruption, use filesystem snapshots or database dump commands (PostgreSQL pg_dump, SQLite .backup, MySQL mysqldump) that produce consistent backups without downtime.

For a complete automated backup workflow that ships snapshots to S3-compatible object storage, see the Restic + Rclone backup guide. Restic handles deduplication and encryption; Rclone handles multi-destination uploads. The same setup works for any Docker volume.

Backup cadence: Daily backups to remote storage are a reasonable baseline for actively used tools. Use a 30-day retention window minimum — long enough to recover from mistakes discovered weeks later. For critical data, extend to 90 days and use a secondary destination.

Restore testing: A backup that has never been restored is a backup you cannot trust. Once a month, restore your CrowdSec backup to a separate Docker Compose stack on different ports and verify the data is intact. This catches silent backup failures, script errors, and volume permission issues before they matter in a real recovery.

Security Hardening

Self-hosting means you are responsible for CrowdSec's security posture. The Docker Compose setup provides a functional base; production deployments need additional hardening.

Always use a reverse proxy: Never expose CrowdSec's internal port directly to the internet. The docker-compose.yml binds to localhost; Caddy or Nginx provides HTTPS termination. Direct HTTP access transmits credentials in plaintext. A reverse proxy also centralizes TLS management, rate limiting, and access logging.

Strong credentials: Change default passwords immediately after first login. For secrets in docker-compose environment variables, generate random values with openssl rand -base64 32 rather than reusing existing passwords.

Firewall configuration:

ufw default deny incoming
ufw allow 22/tcp
ufw allow 80/tcp
ufw allow 443/tcp
ufw enable

Internal service ports (databases, admin panels, internal APIs) should only be reachable from localhost or the Docker network, never directly from the internet.

Network isolation: Docker Compose named networks keep CrowdSec's services isolated from other containers on the same host. Database containers should not share networks with containers that don't need direct database access.

VPN access for sensitive services: For internal-only tools, restricting access to a VPN adds a strong second layer. Headscale is an open source Tailscale control server that puts your self-hosted stack behind a WireGuard mesh, eliminating public internet exposure for internal tools.

Update discipline: Subscribe to CrowdSec's GitHub releases page to receive security advisory notifications. Schedule a monthly maintenance window to pull updated images. Running outdated container images is the most common cause of self-hosted service compromises.

Troubleshooting Common Issues

Container exits immediately or won't start

Check logs first — they almost always explain the failure:

docker compose logs -f crowdsec

Common causes: a missing required environment variable, a port already in use, or a volume permission error. Port conflicts appear as bind: address already in use. Find the conflicting process with ss -tlpn | grep PORT and either stop it or change CrowdSec's port mapping in docker-compose.yml.

Cannot reach the web interface

Work through this checklist:

Confirm the container is running: docker compose ps
Test locally on the server: curl -I http://localhost:PORT
If local access works but external doesn't, check your firewall: ufw status
If using a reverse proxy, verify it's running and the config is valid: caddy validate --config /etc/caddy/Caddyfile

Permission errors on volume mounts

Some containers run as a non-root user. If the Docker volume is owned by root, the container process cannot write to it. Find the volume's host path with docker volume inspect VOLUME_NAME, check the tool's documentation for its expected UID, and apply correct ownership:

chown -R 1000:1000 /var/lib/docker/volumes/your_volume/_data

High resource usage over time

Memory or CPU growing continuously usually indicates unconfigured log rotation, an unbound cache, or accumulated data needing pruning. Check current usage with docker stats crowdsec. Add resource limits in docker-compose.yml to prevent one container from starving others. For ongoing visibility into resource trends, deploy Prometheus + Grafana or Netdata.

Data disappears after container restart

Data stored in the container's writable layer — rather than a named volume — is lost when the container is removed or recreated. This happens when the volume mount path in docker-compose.yml doesn't match where the application writes data. Verify mount paths against the tool's documentation and correct the mapping. Named volumes persist across container removal; only docker compose down -v deletes them.

Keeping CrowdSec Updated

CrowdSec follows a regular release cadence. Staying current matters for security patches and compatibility. The update process with Docker Compose is straightforward:

docker compose pull          # Download updated images
docker compose up -d         # Restart with new images
docker image prune -f        # Remove old image layers (optional)

Read the changelog before major version updates. Some releases include database migrations or breaking configuration changes. For major version bumps, test in a staging environment first — run a copy of the service on different ports with the same volume data to validate the migration before touching production.

Version pinning: For stability, pin to a specific image tag in docker-compose.yml instead of latest. Update deliberately after reviewing the changelog. This trades automatic patch delivery for predictable behavior — the right call for business-critical services.

Post-update verification: After updating, confirm CrowdSec is functioning correctly. Most services expose a /health endpoint that returns HTTP 200 — curl it from the server or monitor it with your uptime tool.

See all open source security tools at OSSAlt.com/categories/security.

The SaaS-to-Self-Hosted Migration Guide (Free PDF)