Introduction

I have witnessed my share of network shutdowns. Started a long time ago in ’93 with networking—back in the days when PSTN and data muxing were the real challenges. Then the Slammer worm hit in 2003, and that was a wake-up call. These days I lead PJ Networks Pvt Ltd and help businesses build zero-trust security (I have three banks as customers last quarter itself).

Returned a few days ago from DefCon with way too much going on in my head from the Hardware Hacking Village. But this post is not about my nostalgia, instead it is about DDoS attacks and how to thwart them using Fortinet firewalls.

DDoS Mitigation with Fortinet – Quick Take

If you don’t have time for the full read, here’s the short version:

• If FortiDDoS is not deployed, implement traffic analysis tools to detect traffic anomalies at an early stage.
• Rate limit non-critical services.
• Use geo-blocking for places that do not require access to the server.
• Use behavior-based anomaly detection instead of only static rules.
• Log everything—so when an attack does occur, you can understand what happened.

Okay, now let’s get into the weeds.

Understanding DDoS Attacks

DDoS (Distributed Denial-of-Service) attacks aim to bombard your servers with overwhelming amounts of traffic until they break—derailing applications, websites, and in some cases, entire businesses.

And here’s the kicker: DDoS attacks are no longer just a matter of volume.

• Application Layer Attacks: These are targeted on web apps, APIs, and authentication systems as opposed to just overwhelming your network.
• IoT Device Botnets: Old fashioned botnets are a thing of the past. Attackers use insecure IoT devices to increase their attack strength.
• Low & Slow Attacks: These types don’t claim your entire network.

Old-fashioned firewalls can’t distinguish between attacks and legitimate traffic. But Fortinet? It features AI-powered adaptive filtering (yes, I’m also skeptical of AI in security, but this works when properly tuned).

How Fortinet Detects & Blocks DDoS

FortiDDoS learns—and that’s why I keep coming back to it regardless of the industry of the Fortinet firewalls I work with (banks, healthcare, large enterprise).

Fortinet’s differentiating factors include the following:

• Real-Time Traffic Analysis: It doesn’t just set rules; instead, Fortinet uses constant analysis of incoming traffic (anomalies, spikes, and abnormal patterns). No one is waiting for the attack to escalate.
• Behavior-Based Detection: Traditional firewalls generally either block traffic at certain IP addresses, or at predefined thresholds. Fortinet analyzes network behavior over time so that even subtle attacks can be detected.
• ASIC Processors Dedicated to DDoS: Using specific ASIC processors, Fortinet firewalls perform hardware-based detection, inspecting packets without the latency that accompanies software-based DDoS mitigation tools.
• Geolocation-Based Blocking: Geo-blocking blocks entire continents from even trying, such as North Korea or a dubious VPS range, if your servers don’t need to serve traffic from them.
• Rate Limiting and Traffic Shaping: Fortinet allows you to rate-limit requests and carefully control packet flows, ensuring a sudden traffic spike doesn’t bring down the system.

Firewall Settings to Prevent DDoS Attacks

Want maximum protection? Configure your Fortinet firewall as follows:

1. Enable FortiDDoS: Ensure that all anomaly-based detection is active, which will help the firewall catch abnormal spikes.
2. Enable SYN flood protection: Most of the attacks begin with SYN floods. Configure SYN cookies in your FortiGate firewall. SYN cookies never overload the system to bear real clients.
3. Employ Rate Limiting on Commonly-Used Ports: Limit requests per second to something sustainable for web servers, login portals, APIs, etc.
4. GeoBlock with Caution: Block traffic from countries with no possibility of legit users.
5. Restrict to Critical Services Only: If a service doesn’t require public traffic, confine it to approved IP ranges.

And one last thing—watch logs like a hawk. I’ve lost count of how many times I’ve seen an attack in its infancy simply by doing a good job of logging everything.

DDoS Mitigation Solutions by PJ Networks

We are PJ Networks Pvt Ltd, a security solutions company. DDoS mitigation is a strategy, not a product—and firewalls are just one piece of the puzzle. Here’s how we approach it:

1. Custom Firewall Deployments: We don’t install things the same way for everyone. Be it with a banking system, SaaS product, or internal IT infrastructure—we adjust the Fortinet settings to match your individual risk profile.
2. Advanced Threat Monitoring: DDoS isn’t always immediate. At times attackers scout for weaknesses weeks ahead of a full-blown attack. Our SOC follows the early warning signs of an attack.
3. Traffic Scrubbing & Mitigation Plans: Before it hits your infrastructure, we direct scrub dirty traffic—your Fortinet solutions are integrated for high-risk clients.
4. Importance of Zero Trust & Network Segmentation: In one of the largest banks we partnered with, we discovered a critical issue—excess lateral movement. We took a microsegmented approach to zero-trust principles to prevent DDoS attacks from propagating internally.

Conclusion

Denial-of-Service attacks aren’t going away. They’re evolving—more sophisticated, more targeted, and often employed as diversions from larger security incursions.

However, if you set up Fortinet firewalls correctly, you keep many attacks from crippling your servers:

• Automatically detects traffic patterns with FortiDDoS.
• Rate limiting & SYN flood protection clog up the line for malicious requests.
• Only allow data to connect with traffic shaping and geo-blocking.
• Ongoing monitoring prevents attacks from going too far.

You’re not just DDoS protected, you still have your whole stack on the other side—it’s a drop in the ocean. Make your network harder, log everything, and—if you have no idea how to do these things—hire professionals to do it right.

Want assistance in deploying a DDoS-proof firewall? PJ Networks Pvt Ltd has you covered.