DDoS attacks, which try to shut down online services by sending a lot of traffic to them at once, are a major threat to website security. Investing in DDoS prevention is an important part of any online business’s cyber defense plan. In this article, we’ll explain different methods that can be used to stop DDoS attacks: firewalls, GRE tunneling, and proxy. We’ll explain the benefits of the proxy approach, and why Gcore Security uses its subtype—reverse proxy—to provide the ultimate DDoS protection.
A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. Firewalls serve as a barrier between a trusted network (like your personal computer or a company’s network) and untrusted networks (like the Internet), allowing only safe, approved traffic to pass through. They are used to protect networks and devices from unauthorized access and diverse types of cyberthreats, including viruses, worms, hacking attempts, and even DDoS attacks.
While firewalls offer a good level of DDoS defense, their effectiveness has limits:
- Limited filtering: Traditional firewalls rely on predefined rules to identify and block malicious traffic. DDoS attackers often craft attack packets to mimic legitimate traffic, effectively bypassing these static rules. As a result, firewalls might simply miss the signs of a DDoS attack and fail to stop malicious traffic.
- Resource constraints: During large-scale DDoS attacks, the sheer volume of malicious traffic can overwhelm firewalls, leading to resource exhaustion and service disruptions. A firewall isn’t specifically designed to handle DDoS attacks so it may use all its capacity trying to process the traffic. Consequently, legitimate traffic may be unable to pass through, resulting in service disruptions, meaning the DDoS attack was a success.
- Lack of specialization: Firewalls are designed for broad security purposes and lack the specialized tools and techniques needed to combat the dynamic nature of contemporary DDoS attacks. Amplification and reflection vectors, common in DDoS attacks, are beyond the scope of standard firewall capabilities.
Firewalls do provide a basic level of defense against DDoS attacks, but have serious shortcomings and can’t be relied on by businesses serious about their security posture.
GRE (generic routing encapsulation) tunneling establishes a tunnel between customers and scrubbing networks to mitigate the impact of DDoS attacks. When a DDoS attack is detected, the targeted network can redirect the excessive traffic into a GRE tunnel. This tunnel leads to a separate network infrastructure known as a scrubbing center, which filters out the malicious traffic and only allows legitimate traffic to pass through. Once cleaned, this traffic is sent back via another GRE tunnel to the original network, thus minimizing the impact of the DDoS attack on the primary infrastructure. This method enables the network to continue functioning normally during an attack, as the DDoS traffic is effectively quarantined and dealt with separately. It’s most effective when paired with BGP.
There are, however, challenges associated with their use:
- Complex to set: Setting up GRE tunnels involves intricate network configuration on both ends, requiring expertise in routing protocols and firewall rules. This complexity can lead to misconfigurations, delays, and increased vulnerability during initial setup.
- Scalability issues: Traditional GRE tunnels lack inherent scalability mechanisms. During large-scale DDoS attacks, the sheer volume of traffic can overwhelm and disrupt established tunnels, causing service interruptions.
- Limited control: GRE tunnels encapsulate all traffic within the tunnel, making it impossible to see what’s contained in individual data packets. This means it’s difficult to identify and target specific malicious traffic within the tunnel, potentially allowing some attack packets to slip through the cracks.
- Performance implications: GRE tunneling adds an additional layer of encapsulation and decapsulation to network traffic. While the network is being protected from the DDoS attack, the additional processing required for the GRE tunneling can slow down the network’s performance. This can be particularly detrimental in time-sensitive applications or during high-traffic scenarios, creating bottlenecks and disrupting user experience.
A standard proxy is an intermediary between your computer (or local network) and the internet. When you send a request to the internet, it first goes to the proxy server, which then forwards it to the internet on your behalf. This process also works in reverse when data is being sent back to your computer. It helps protect you from online threats by hiding your identity; specifically by masking your IP address, which is your unique identifier on the internet. This makes it harder for online threats to find and attack your computer.
A reverse proxy works in the opposite way. It receives requests from the internet and forwards them to servers in an internal network. Those servers respond to the reverse proxy, which then sends the received data to the clients on the internet. It shields servers from direct interaction with the internet.
During a DDoS attack, a reverse proxy is an effective shield. Rather than the attack traffic directly hitting the target server (which could overwhelm it and disrupt its service,) the reverse proxy absorbs and filters out the malicious traffic before it reaches the target server. This means the server is shielded from the attack while legitimate traffic can still access the server.
The reverse proxy and GRE methods provide several advantages for DDoS mitigation over a traditional firewall approach:
- Traffic filtering and distribution: The reverse proxy or scrubbing center acts as an intermediary network, receiving all incoming traffic and then forwarding it to the server. This enables for traffic content inspection—including HTTP headers, URLs, and payload—allowing the identification and filtering out of harmful traffic, as well as efficient load distribution.
- Anonymizing the origin server: Hiding the IP address of the origin server makes it more difficult for attackers to target the server directly with DDoS attacks, as they essentially attack the intermediary—the reverse proxy or scrubbing center—instead of the server itself.
- Scalability and flexibility: Proxies and scrubbing centers can be scaled to handle large volumes of traffic, making them more effective against volumetric attacks. They can also be adjusted quickly to respond to different types of DDoS attack strategies.
Reverse proxies offer two additional benefits.
- Load balancing: Many reverse proxy servers provide load balancing, distributing incoming requests across multiple servers. This helps in managing traffic spikes during a DDoS attack while simultaneously improving overall server performance and uptime.
- Application layer protection: Reverse proxies are particularly effective against application-layer (Layer 7) attacks. They can inspect and filter incoming HTTP/HTTPS requests, blocking malicious traffic based on specific behaviors or patterns.
When compared to GRE tunneling, reverse proxies offer better traffic filtering, application-layer protection, and load balancing, making them ideal for combating sophisticated DDoS attacks. GRE tunnels excel in raw data flow management and scalable distribution, potentially providing stronger server anonymity, but they lack the granularity and adaptability of reverse proxies for advanced DDoS mitigation.
Gcore DDoS Protection via Reverse Proxy
Gcore DDoS Protection employs reverse proxy technology, offering a comprehensive shield against various types of DDoS attacks. Our infrastructure intercepts incoming traffic, filters potential threats, and ensures only legitimate requests reach the server. This system is especially effective against volumetric, protocol, and application-layer attacks.
Our reverse proxy approach contributes to several of the benefits afforded by Gcore DDoS Protection:
- Proprietary, ML-driven DDoS protection solution: Advanced algorithms detect low-frequency attacks from the first query, with a near-perfect false positive rate of less than 0.01%.
- Scalable defense: Our robust network shrugs off even the most potent attacks, exceeding 1 Tbps in total filtering capacity and with a proven record stopping attacks above that size.
- Performance boost: Streamlined traffic management translates to faster loading times and an uninterrupted user experience.
- Seamless integration: Integrate Gcore DDoS Protection with your existing setup for hassle-free defense.
- Robust SLA: Enjoy guaranteed 99.99% uptime.
- Real-time insights: Monitor attack details in real time through our intuitive control panel.
- 24/7 technical support: Our expert team is always available for questions and support.
Reverse proxies are powerful tools for defending against DDoS attacks. They offer advanced capabilities compared to traditional firewalls while being easier to set up and scale than GRE tunneling. These features make them a valuable weapon in modern cybersecurity arsenals, providing a nuanced and adaptable approach to combating the evolving threat of DDoS attacks.
DDoS threats evolve, but Gcore stays ahead of the curve. Get Gcore DDoS Protection today and focus on your core business while we take care of your security.