Anti-DDoS technology

Welcome to Legionhoster, Your Future Hosting Partner

A unique system for protecting against distributed denial-of-service attacks


The pre-firewall

The pre-firewall is the first component of our VAC system. It is fully managed by Legionhoster, and applies rules that define filters directing data packets to the Firewall Network (see below). These rules are applicable to all Legionhoster solutions. When a DDoS attack is launched, the pre-firewall manages part of the filtering, and sends the rest to the Firewall Network, which has customizable rules. Our pre-firewall is based on an Arista 7508R, which can reach a communication capacity of 28.8 Tbit/s. Isolation by VRF then routes the traffic through our system’s successive stages.

The Firewall Network

This is the second component of the VAC. The Firewall Network is a solution that limits exposure to attacks from the public network. It activates automatically as soon as a DDoS attack starts. You can configure it by creating up to 20 rules, which will filter packets more finely and can be adapted to fit your server’s activity. Each rule is a specific authorization you can use to optimize protection for your service. This firewall activates automatically whenever a DDoS attack begins, and you cannot deactivate it until the attack is over. This is why it is important to keep your firewall rules up-to-date.

Shield and Armor

The Shield and Armor hardware intervenes if an attack is more targeted, and offloads part of the filtering from the server’s processor. The Shield intervenes if an attack uses an amplification technique (DNS amp, NTP amp). Armor is the most advanced filter in our VAC, and intervenes in mitigating the very strongest attacks.




An attack is detected using real-time analysis of the netflow sent by the routers, which analyze 1/2000 of the traffic that goes through them. The VAC analyes the reports, and compares them to the characteristics of DDoS attacks. If a similarity is detected, mitigation is then triggered automatically. The analysis of characteristics is measured by packets per second, or in bytes over several protocols, including: DNS ; ICMP ; IP fragmentation, Null and Private ; TCP Null, RST, SYN, ACK ; UDP.


Vacuuming is one of the main features that makes the Legionhoster anti-DDoS solution stand out. Channeling a DDoS attack requires a high capacity to bear the load. With its 15 Tbit/s network, Legionhoster infrastructures can absorb a very high volume of traffic during DDoS attacks. Another specific feature of the Legionhoster VAC is the fact that it is replicated in 10 data centers across three continents. The VAC is activated simultaneously in all of these data centers, so that all regions can combine their power and absorb the traffic. They have a combined capacity of more than 4 Tbit/s.