It was late at night. The room light was still on, and the flashing red alerts on my screen made my heartbeat quicken. Website traffic had suddenly surged, and a flood of abnormal requests told me something was wrong — our site was under attack.
I immediately pulled up the backend and opened the logs, trying to trace the source. Just then, my phone rang. It was my colleague, his voice filled with anxiety:
“The website is down. Customers are complaining.”
That’s when I realized the situation was no longer just a simple outage — it was a matter of business survival.
At that moment, I remembered a talk I attended months earlier. A senior security expert mentioned an open-source Web Application Firewall developed by Chaitin: Safeline WAF — known for its strong protection, easy deployment, and completely free licensing. With no time to waste, I deployed it immediately. To my surprise, it worked seamlessly and helped us survive the crisis.
So today, I want to introduce you to Safeline WAF — one of the simplest, most powerful, and truly user-friendly free WAFs available.
Safeline WAF Official Website
https://safepoint.cloud/landing/safeline
What Is Safeline WAF?
Safeline WAF is a free, open-source, full-featured Web Application Firewall built by Chaitin Tech over the course of nearly 10 years. Powered by an industry-leading semantic detection engine, it sits as a reverse proxy in front of your website and blocks malicious requests before they ever reach your server.
Its detection capabilities are driven by intelligent semantic analysis and designed specifically for the community — keeping attackers firmly outside your perimeter.
Core Features
1. Block Web Attacks
Safeline protects against all common Web attacks, including:
- SQL Injection
- XSS
- Code Injection
- OS Command Injection
- CRLF Injection
- XXE
- SSRF
- Path Traversal … and more.
2. Rate Limiting
Throttle request rates to defend against:
- CC attacks
- Brute-force attempts
- Sudden traffic spikes
- Abuse from bots or automated tools
3. Human Verification
Most traffic on the internet is automated — crawlers, scanners, worms, exploit tools.
With human verification enabled, real users pass while malicious bots are blocked.
4. Access Authentication
Safeline’s built-in “Authentication” feature helps mitigate unauthorized access issues. Users must enter credentials you configure, otherwise they are denied.
5. Dynamic Protection
Safeline injects dynamic, randomized variations into your HTML and JS without altering visible content, making static payload-based attacks extremely difficult.
What Exactly Is a WAF?
A WAF (Web Application Firewall) works at the application layer (HTTP/HTTPS) and protects web applications from a wide range of attacks. It’s different from a traditional firewall, which focuses on network-level traffic.
A WAF can detect and block:
- SQLi
- XSS
- CSRF
- SSRF
- WebShell uploads
- Malicious bot traffic … and other threats targeting your web layer.
How to Install Safeline
Minimum Requirements
- OS: Linux
- Architecture: x86_64 or arm64
- Docker: 20.10.14 or higher
- Docker Compose: 2.0.0 or higher
- Hardware: 1 Core / 1 GB RAM / 5 GB Disk
One-Command Installation (Recommended)
bash -c "$(curl -fsSLk https://waf-ce.chatin.cn/release/latest/manager.sh)"
Manual and offline installation methods are also available on the official website.
How to Use It
Once installation is complete, open:
https://<safeline-ip>:9443/
Make sure port 9443 is open.
Testing Safeline
The official demo site lets you test WAF protection using simulated attacks.
- Normal traffic → site loads fine
- Malicious traffic → Safeline automatically detects and blocks the request
How Safeline Works Internally
Safeline filters and monitors all HTTP traffic between users and your backend servers. It detects malicious patterns such as:
- SQLi
- XSS
- Code/Command Injection
- LDAP Injection
- Xpath Injection
- RCE
- XXE
- SSRF
- Path Traversal
- Backdoor traffic
- Brute-force attempts
- CC attacks
- Crawlers
Safeline acts as a reverse proxy, receiving the traffic first, detecting and cleaning malicious payloads, and forwarding only safe traffic to your web servers — ensuring attackers never reach your backend.
Highly Recommended
Safeline WAF is the result of nearly a decade of engineering by Chaitin Tech.
It offers:
- Zero-friction setup
- Enterprise-grade protection
- High performance
- Completely free & open-source
If you’re running a website, API, or any public-facing service, Safeline is an excellent choice to keep your infrastructure safe.
Give it a try — and let Safeline WAF guard your site from malicious traffic.
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