How to Stop a DDoS Attack and Protect Your Network

A DDoS attack doesn’t knock. It crashes through the front door.

One moment, your site is running smoothly. Next, it’s flooded with bogus traffic so fast your real users can’t even log in. Distributed denial-of-service (DDoS) attacks don’t rely on finesse; they overwhelm your systems with brute force. And they’re getting easier to launch every day. So much so that even someone without technical skills can disrupt your entire online operation.

That’s why knowing how to stop a DDoS attack before it brings your business to a halt isn’t just smart; it’s survival.

Even if you’re not a security expert, you can prepare your business for these attacks. Tools like DDoS protection software, web application firewalls (WAFs), and real-time monitoring can detect the signs early and keep your systems online. Whether you run a high-traffic e-commerce site or manage enterprise-level infrastructure, having a prevention and response plan in place is critical.

Why do DDoS attacks happen?

What motivates someone to launch a DDoS attack, and why might your business be a target? The truth is, it doesn’t take much these days. DDoS attacks are no longer reserved for sophisticated cybercriminals or nation-state hackers. They’re widely available, surprisingly affordable, and often launched for reasons that have nothing to do with you. 

Common reasons behind DDoS attacks

Let’s break down the most common motives behind these attacks, and why your company might be targeted. 

• Financial extortion: Some attackers hit websites with traffic floods and then demand payment to stop. This form of ransom-DDoS (or RDoS) is growing fast, especially in industries where uptime is business-critical.
• Ideological activism: Hacktivists may launch attacks to protest a company’s policies, affiliations, or even their perceived role in social or political issues. These attacks are often timed with public events or announcements.
• Competitive sabotage: In some markets, such as e-commerce, gaming, or crypto, competitors use DDoS attacks to slow down or crash rival services during peak hours or launches.
• Revenge or internal threats: Disgruntled former employees, contractors, or even unhappy customers might use DDoS as a form of digital retaliation.
• Just because they can: Thanks to “DDoS-as-a-service” platforms on the dark web, anyone with $5 and an internet connection can launch an attack. No technical skills required.

How do you know if you're under a DDoS attack?

Recognizing the signs of a DDoS attack is the first step to preventing downtime. If you experience any of the following problems, then you could be under attack.

• Network traffic spike is one of the most common signs of a DDoS attack. Organizations experiencing sudden inbound traffic increase may be subject to ongoing attacks that overwhelm the network infrastructure and consume more server resources. That's why it's important to monitor traffic patterns and spikes to identify in-progress attacks. 
• Slow access to local and remote files is another typical sign. Since a DDoS attack congests a network infrastructure with malicious traffic, it may increase latency and packet loss. Organizations must keep an eye on network performance degradation and speed of network-dependent activities to understand if they are subject to an attack. 
• Inaccessible website along with error messages like 'service unavailable' is another sign. This happens because servers may crash due to an excessive volume of incoming traffic which causes service unavailability.
• Network log abnormalities can also help an organization understand whether they are subject to a DDoS attack. For example, businesses can look at repetitive resource requests, too many connection requests from specific internet protocol (IP) addresses, and traffic distribution across network segments to understand if they have been through DDoS attacks. 

If you start seeing any of the signs above, you should take a closer look at what’s going on, but don’t panic. Sometimes you’ll experience connectivity issues because of traffic spikes and legitimate usage, so service disruption doesn’t always mean that you’re under attack!

However, if you notice anything unusual or prolonged disruption to the service, you should investigate further. If you are being subjected to a DDoS attack, the earlier you react, the better. 

What are the most effective DDoS prevention methods?

Organizations seeking to prevent DDoS attacks must adhere to network security best practices, adopt proactive security measures, and use specialized DDoS prevention tools. Here are a few methods you can implement at your organization.

• Attack surface reduction limits the number of entry points an attacker uses to exploit a network or system and launch an attack. This DDoS attack prevention method minimizes the attackable surface area by using network segmentation, access control lists (ACL), security assessments, and firewall configurations. Organizations can also implement load balancing software to restrict traffic to and from certain locations, ports, protocols, and applications. 
• Anycast network diffusion uses a network addressing and routing method called anycast network to distribute volumetric traffic spikes across distributed servers. This DDoS attack prevention method redirects traffic to the nearest available server during an attack. This redirection minimizes service disruption while letting an organization deflect malicious traffic with distributed networks. 
• Real-time, adaptive threat monitoring uses log monitoring tools to analyze network traffic patterns, detect unusual activities, and block malicious requests. Organizations using this method combine machine learning algorithms and heuristic analysis to proactively detect threats, counter DDoS attacks, and minimize downtime.
• Caching uses content delivery networks (CDNs) or caching servers to reduce the number of workload requests origin servers tackle. Users can still retrieve information from the cached content. This DDoS attack prevention mechanism stops malicious requests from overloading origin servers, especially during volumetric traffic floods. The result is improved website performance and reduced strain on the infrastructure during an attack. 
• Rate limiting restricts network traffic for a period to prevent specific IP addresses from overwhelming web servers. This mechanism is ideal for tackling application layer or protocol or botnet-based attacks that send too many requests and overwhelm server resources during an attack. Organizations adopting rate limiting can easily block traffic exceeding pre-defined thresholds, maintain system resources, and defend against DDoS attacks. 

Here's a quick structured response framework to prepare for, manage, and recover from a DDoS attack. Each phase has distinct priorities to minimize damage and accelerate recovery.

6 proven tips to stop a DDoS attack and prevent future ones

Preparation is almost always the best line of defense against a DDoS attack. Proactively blocking traffic is better than being reactive. Since preventing a DDoS attack isn’t possible all the time, you should have a combination of prevention and response techniques in place to address an incident with minimal disruption. Ultimately, the faster you or your team react, the less damage is done.

1. Change the server IP or call your ISP immediately

When a full-scale DDoS attack is underway, changing the server IP and DNS name can stop the attack in its tracks. However, if the attacker is vigilant, then they might start sending traffic to your new IP address as well. If changing the IP fails, you can call your internet service provider (ISP) and request that they block or reroute the malicious traffic.

2. Monitor your website traffic

A spike in website traffic is one of the main indicators of a DDoS attack. Using a network monitoring tool that monitors website traffic will tell you the moment a DDoS attack starts up. Many DDoS protection software providers use alerts and thresholds to notify you when a resource receives a high number of requests. While traffic monitoring won’t stop an attack, it will help you to respond quickly and begin mitigation should an attacker target you.

3. Set up a redundant network architecture

Setting up your network architecture to be resistant to a DDoS attack is an excellent way to keep your service up and running. You should spread out key resources like servers geographically so that it is more difficult for an attacker to put you offline. That way, even if one server gets attacked, you can shut it down and still have partial service for your users.

4. Use a web application firewall 

A WAF system is used to filter HTTP traffic between an application and the internet. When a cybercriminal targets a DDoS attack at the application layer, the application firewall automatically blocks malicious HTTP traffic before it reaches your site. You can decide what traffic gets filtered by configuring policies to determine which IP addresses will be whitelisted or blacklisted.

5. Configure firewalls and routers!

Configuring network devices like firewalls and routers is essential for cutting down on entry points into your network. For instance, a firewall will help to stop cyberattackers from detecting your IP address, so they won’t have anywhere to send traffic. Similarly, routers have DDoS protection settings and filters that you can use to control the access of protocols and packet types. 

6. Enable geo-blocking (country blocking)

Geo-blocking is the practice of blocking out traffic from foreign countries where DDoS attacks are frequent. The majority of DDoS traffic comes from China, Vietnam, South Korea, and Taiwan, so blocking traffic from these regions could limit your exposure. While attackers can work their way around geo-blocking, it can reduce your vulnerability to overseas botnets.

Frequently asked questions about DDoS attacks

Got more questions? We have the answers.

Q1. What are the types of DDoS attacks?

DDoS attacks fall into three main categories:

• Volumetric attacks (e.g., UDP floods) aim to saturate bandwidth.
• Protocol attacks (e.g., SYN floods) exploit server resources.
• Application layer attacks (e.g., HTTP floods) mimic real user behavior to crash web apps.

Each type targets different infrastructure layers, requiring layered defenses to fully mitigate.

Q2. How does a web application firewall help against DDoS?

A WAF filters incoming HTTP/HTTPS traffic to block malicious requests targeting your application layer. It can stop bots, apply rate limits, challenge suspicious users, and help mitigate Layer 7 DDoS attacks without affecting real traffic.

Q3. Can a DDoS attack cause permanent damage to my infrastructure?

Not usually in a physical sense, but extended attacks can lead to corrupted data, interrupted workflows, lost revenue, and degraded user trust, especially if services remain offline too long.

Q4. Is cloud hosting safer from DDoS attacks than on-premise servers?

Generally, yes. Cloud platforms often come with built-in traffic distribution, autoscaling, and DDoS filtering, but they still require proper configuration and third-party protection for advanced threats.

Q5. How long do DDoS attacks usually last?

Some attacks last minutes, while others last days. Attackers may also use short bursts or rotating techniques to evade detection and maximize disruption.

Outsmart the outage

Unfortunately, even with all the preparation in the world, a strong DDoS attack is tough to beat. If you're successful in fighting off the attack, you're still likely to suffer some form of disruption. However, with the right preparation in place, you can reduce the likelihood of an attack putting you out of action.

During an attack, all you can do is notify your employees and your customers to explain performance issues. A social media post will let your customers know there's a problem and that you're working on fixing it.

With the right measures in place, you will be able to limit the damage even if you can't prevent it completely. The important thing is to take action and start building up your defenses early. In the event you do fall victim to an attack, keep a log of source IP addresses and other data for future reference in case there's a follow-up attack.

Want to spot unusual traffic patterns before your systems go down? Explore the top-rated network monitoring software to improve visibility, set smart alerts, and stay ahead of the next DDoS threat.

This article was originally published in 2019. It has been updated with new information.