Websites, online stores, APIs, and other services hosted on a VPS need to remain accessible to users even during sudden increases in malicious traffic. During a DDoS attack, a large number of requests or packets can overwhelm the network connection and server resources, resulting in slower performance or complete service disruption.

Standard VPS security measures help restrict unauthorized access and address other threats, but they are not sufficient on their own against large-scale DDoS attacks. Effective protection should detect and filter malicious traffic at the network infrastructure level before it reaches the server.

This is why, when choosing a VPS, it is important to understand how DDoS protection works, which attacks it can mitigate, and what additional security mechanisms the provider offers.

Why Does It Matter for VPS Hosting?

A virtual server can support demanding applications and services, but its resources and network capacity are still limited. A distributed denial-of-service (DDoS) attack can direct a massive number of requests or a large volume of traffic toward a service, exhausting available bandwidth, connection capacity, or application resources and preventing legitimate users from accessing it. 

Network-layer attacks can saturate the available connection, while application-layer attacks can exhaust server resources without requiring exceptionally high bandwidth.

This is why DDoS protection is important for VPS hosting. It helps prevent malicious traffic from overwhelming the infrastructure, allowing services to remain available to legitimate users. Adding more CPU or RAM can help accommodate normal traffic growth, but it cannot prevent unwanted traffic from saturating the network connection.

A real-world example of the scale of such attacks is a DDoS attack recorded by Cloudflare in May 2025. The attack targeted a hosting provider and peaked at 7.3 Tbps, generating 37.4 TB of traffic in just 45 seconds. It was automatically detected and mitigated by Cloudflare's DDoS protection infrastructure. 

The incident demonstrates why protection against large-scale attacks requires sufficient network capacity and the ability to filter malicious traffic before it reaches the protected server.

How Are DDoS Attacks Detected and Mitigated?

The exact approach depends on the provider's infrastructure, but DDoS protection typically involves several stages: traffic monitoring, detection of unusual activity, and filtering of malicious requests or packets. In automated systems, these actions can take place without administrator intervention.

Detecting Malicious Traffic

DDoS protection systems monitor characteristics such as traffic volume and source, packet behavior, connection counts, and request patterns. When activity deviates from normal behavior, the system can identify the type of attack and activate appropriate protection rules.

Filtering the Attack

Once an attack has been detected, malicious traffic is limited or blocked. Depending on the attack, this may involve dropping specific packets, limiting the number of connections or requests, and applying additional filtering rules. When necessary, traffic can be redirected through dedicated DDoS mitigation infrastructure, which filters unwanted traffic while allowing legitimate requests to continue to the server.

Filtering Traffic Before It Reaches the VPS

During large DDoS attacks, filtering needs to take place outside the VPS itself. If malicious traffic has already saturated the network connection, a firewall running on the server cannot restore the exhausted capacity. Network-level protection therefore aims to block the attack earlier and allow only legitimate traffic to reach the VPS.

Example: An online store normally receives several hundred requests per minute, but suddenly tens of thousands of requests begin arriving from multiple sources. The DDoS protection system detects the unusual increase, analyzes the traffic, and applies rules to restrict malicious requests. These requests are filtered at the network infrastructure level, while legitimate traffic continues to the VPS server. As a result, real customers can continue browsing products and placing orders without all incoming traffic reaching and consuming the server's resources.

What Is the Difference Between L3, L4, and L7 DDoS Protection?

DDoS attacks can target different layers of network communication. Protection is therefore commonly divided into L3, L4, and L7 based on the type of traffic involved and the resources the attack attempts to overwhelm.

Layer 3 (L3) DDoS Protection

Layer 3 protection operates at the network layer and primarily addresses attacks designed to overwhelm available network capacity. It analyzes IP and ICMP traffic and filters malicious packets before they reach the protected infrastructure. Its main purpose is to maintain network connectivity even when large volumes of unwanted traffic are generated.

Example: Imagine the VPS server as an office building and the network infrastructure as the surrounding area and roads leading to it. During an L3 attack, a huge crowd heads toward the building at the same time and blocks access to it. The role of L3 protection is to stop unwanted visitors before they reach the entrance, allowing employees and legitimate visitors to continue reaching the building.

Layer 4 (L4) DDoS Protection

Layer 4 protection operates on transport protocols such as TCP and UDP. It protects against attacks that generate large numbers of packets or connections in an attempt to exhaust available network and server resources. These mechanisms help restrict malicious traffic without disrupting legitimate TCP and UDP connections.

Continuing the example: With an L4 attack, the problem has moved closer to the building's entrance. Large numbers of visitors attempt to enter through different doors at the same time or repeatedly begin the identification process without actually completing it. Security personnel now need to control how access takes place and restrict suspicious attempts without interfering with legitimate visitors.

Layer 7 (L7) DDoS Protection

Layer 7 protection focuses on the application itself and analyzes requests such as HTTP and HTTPS traffic directed at websites and APIs. With this type of attack, malicious requests can resemble normal user activity, which means they cannot always be identified based on traffic volume alone. Request behavior analysis, rate limiting, filtering rules, and a Web Application Firewall (WAF) can be used to mitigate these attacks.

Continuing the example: With an L7 attack, the visitor now appears to have a perfectly legitimate reason to be inside the building. Instead of blocking the entrance, they repeatedly make requests to employees and consume their time and resources, preventing them from serving other visitors. Security therefore needs to analyze the visitor's behavior and distinguish normal activity from abuse, similar to how L7 protection analyzes requests made to a website or application.

What Should You Check When Choosing a VPS?

The term "DDoS protection" alone does not indicate which attacks a service can mitigate or how the protection performs during an actual incident. When comparing VPS solutions, check the following characteristics:

• Always-on protection: Check whether traffic is continuously monitored and whether mitigation is activated automatically when an attack is detected. This reduces response time and the need for manual intervention.
• Protection layers: Determine whether the provider offers protection against L3 and L4 attacks and whether L7 protection is available when your application requires it.
• Filtering capacity: Check how much malicious traffic the infrastructure is capable of handling. Do not consider the advertised Tbps figure alone. Look at where filtering takes place, how the network is designed, and how quickly an attack can be mitigated.
• Application-layer protection: If you host a website, online store, or API, check whether you have access to or can add a WAF, rate limiting, and other mechanisms for restricting malicious HTTP and HTTPS requests.
• Monitoring and alerts: Check whether you have access to information about unusual traffic and attacks and whether you receive notifications when an incident is detected.
• Incident response, technical support, and terms: Find out how the provider responds to larger or prolonged attacks, how you can contact the technical team, and whether the protection includes traffic limits, additional charges, or other conditions during a DDoS incident.

Conclusion

If you are looking for a VPS solution with built-in network-level protection, the Cloud VPS we offer at Delta.BG is protected against Layer 3 and Layer 4 DDoS attacks. The infrastructure is designed to detect and filter large-scale malicious traffic before it reaches your VPS instance. At the same time, you retain full root access and control over the server, along with the ability to add the application-level security measures your workload requires.

Our team can help you determine the right configuration for your requirements. Contact us at support@delta.bg or +359 2 4 288 288 to discuss your needs.