SafeLine WAF Review: Can a Free Firewall Really Protect Your Apps?

When it comes to open-source Web Application Firewalls, most developers think of ModSecurity or Nginx-based solutions. But there’s a new player worth checking out: SafeLine WAF.

It’s free, easy to deploy, and still packs in a strong set of protections that usually sit behind commercial licenses. In this post, I’ll walk you through my hands-on experience with SafeLine WAF Personal Edition — from installation to testing, configuration, and a look at what’s included in different versions.

Test Environment

1. Installing Docker

If you don’t already have Docker, install it manually or use the binaries:

wget https://download.docker.com/linux/static/stable/x86_64/docker-24.0.8.tgz
tar -xzvf docker-24.0.8.tgz --strip-components=1 -C /usr/local/bin/

Then configure Docker:

mkdir -p /etc/docker

tee /etc/docker/daemon.json > /dev/null << 'EOF'
{
  "data-root": "/var/lib/docker",
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": { "max-size": "100m" },
  "storage-driver": "overlay2",
  "registry-mirrors": [
    "https://docker.mirrors.ustc.edu.cn",
    "https://hub-mirror.c.163.com"
  ]
}
EOF

Enable and start Docker:

systemctl daemon-reload
systemctl enable docker.service docker.socket
systemctl start docker
docker version

2. Installing Docker Compose

Download the binary:

mkdir -p /usr/local/lib/docker/cli-plugins
wget https://github.com/docker/compose/releases/download/v2.39.2/docker-compose-linux-x86_64
chmod +x /usr/local/lib/docker/cli-plugins/docker-compose
docker compose version

3. Installing SafeLine WAF

There are multiple ways to install:

• One-click install (recommended):

bash -c "$(curl -fsSLk https://waf.chaitin.com/release/latest/manager.sh)" -- --en

If successful, you can log in immediately to the management console.

• Manual installation: For Linux/Docker power users → Guide
• Offline installation: For air-gapped environments → Guide

4. Accessing the Dashboard

Default URL: https://192.168.99.203:9443/

username: admin
password: nxjI9JG8

The UI is clean and intuitive, making it easy to start protecting your apps.

5. Adding a Protected Site

From the dashboard, you can add the web app or API you want to protect. In my test, I added a JavaSec login page.

6. Security Policies

SafeLine comes with built-in protection modules:

• HTTP Flood Protection — rate limiting, waiting rooms, request throttling
• Bot Defense — human verification (no-interaction, slider CAPTCHA), dynamic JS/HTML encryption, replay prevention
• Auth — simple authentication and unified login
• Attack Protection — SQLi, XSS, file upload, file inclusion, command injection, deserialization (Java, PHP, ASP), template injection, CSRF, SSRF, malformed HTTP

7. Testing the Protection

Triggering SQL injection or XSS rules correctly returns a blocked response. Events are logged in real time, with detailed request/response data visible in the dashboard.

8. Handling False Positives

In SafeLine, you can whitelist or blacklist based on conditions such as:

• Source IP
• URL / Path
• GET/POST parameters
• Headers / Body content
• HTTP method
• JA4 fingerprint

9. Logs & Reports

The dashboard includes:

• Statistics & Reports — charts for traffic and attack trends
• Attack Logs — detailed breakdown of blocked attempts
• Access Control — manage blacklists, CC protection, bot defense
• General Settings — protection configs, system logs, console management

Final Thoughts

SafeLine leaves a strong first impression:

✅ Free and easy to install (literally a single command)
✅ Strong security coverage (SQLi, XSS, file uploads, deserialization, etc.)
✅ Clean UI and useful logs

Still, for developers, small teams, or anyone looking for a free WAF that just works, SafeLine is absolutely worth trying.

Join the SafeLine Community

If you continue to experience issues, feel free to contact SafeLine support for further assistance.

• GitHub Repository
• Official Docs
• Discord Community