DDoS attack mitigation with WANGUARD Filter

The Filter provided by WanGuard is an anti-DDoS traffic analyzer and intelligent firewall rules generator designed to protect networks from internal and external threats (availability attacks on DNS, VoIP, Mail and similar services, unauthorized traffic resulting in network congestion), botnet attacks, zero-day worm and virus outbreaks. It includes sophisticated traffic analysis algorithms that are able to detect and side-filter malicious traffic in a granular manner without impacting the user experience or resulting in downtime.

The Filter can be used only in conjunction with the Flow Sensor (for NetFlow, sFlow, jFlow or IPFIX) or the Packet Sensor (for in-line servers, port mirroring, network TAPs).
  • Management and reporting are done from a single web-based Console with a unified, holistic presentation
  • Defends against known, unknown and evolving DoS, DDoS and other volumetric attacks by filtering dynamically any combination of source and destination IPv4 or IPv6 addresses, source and destination TCP ports, source and destination UDP ports, IP protocols, Invalid IP packets, ICMP types, Time To Live field, cpackets lengths, more.
  • Recognizes and blocks malicious traffic in under 5 seconds
  • Does not block or blacklist valid customer traffic
  • Does not require network baseline training or operator intervention
  • Designed to work with a asymmetric routing
  • Per-endpoint flexible threat management tools and an easy-to-use API for scripting the reaction to attack patterns:
    • Alert your NOC staff or the ISP of the attacker using user-defined email templates
    • Send custom Syslog messages to remote log servers or SIEM systems
    • Capture a sample of the attacker's traffic for forensic investigation and legal evidence
    • Execute your own scripts that extend the built-in capabilities:
      • Configure ACLs or execute PIX "shun" commands on routers or firewalls
      • Filter attacking IP addresses by executing “route blackhole” commands on Linux servers
      • Send SNMP TRAP messages to SNMP monitoring stations, etc.
  • Supports multiple packet filtering backends:
    • Software filtering using the NetFilter framework provided by the Linux kernel
    • Hardware-based filtering for 1 or 10 Gbps network cards with Intel's 82599 chipset (Intel X520 NIC, Intel X540 NIC, HP 560 NIC, other vendors), or better
    • Dedicated firewalls and IPSes using helper scripts
  • The cleaning server can be deployed in-line or can scrub the malicious traffic by BGP off-/on-ramping
  • The cleaned traffic can be re-injected downstream into the network with static routing or GRE/IPIP tunneling
  • Easy and non-disruptive installation on common server hardware
  • The most affordable on-premise Anti-DDoS protection and DDoS mitigation software solution on the market
  • Out-of-line server. In the image below, the Filter sends a BGP routing update to the ingress border router that will set the Filter's server as the next-hop for the suspect traffic. The Filter then blocks the malicious traffic, and the cleaned traffic is routed back into the network. This technique, used to send only the traffic received by attacked destinations to the filtering server for cleaning, is called traffic diversion, BGP off-/on-ramping, sink hole routing, side filtering, etc.

    DDoS Defense Topology
  • In-line server configured as router. The Filter runs on a server that resides in the main data-path, configured to be a Linux router.
  • In-line server configured as network bridge. The Filter runs on a server that resides in the main data-path, configured to be an OSI Layer 2 network bridge.
  • Server connected to a network tap or mirroring port. The Filter runs on a server that receives a copy of packets from a network tap or a mirroring port. Direct filtering is not possible, but the Filter is able to generate filtering rules that improve the visibility of attacks and can be applied to other in-line appliances or firewalls.


1 Gbps mitigation 10 Gbps mitigation
Deployment Type:   In-line or out-of-line deployment Out-of-line deployment recommended
CPU: 2.5 GHz dual-core Xeon 2.8 GHz quad-core Xeon
RAM: 2 GB 8 GB
Network Cards: 2 x Gigabit Ethernet 1 x 10 GbE card (Intel 82599 chipset or better)
1 x Gigabit Ethernet
Operating System:   RHEL / CentOS 5, RHEL / CentOS 6, OpenSUSE 12, Debian Linux 6 or 7, Ubuntu Server 12 RHEL / CentOS 5, RHEL / CentOS 6, OpenSUSE 12, Debian Linux 6 or 7, Ubuntu Server 12
Disk Space: 10 GB (including OS) 10 GB (including OS)
* Other Linux distributions might work but have not yet been tested.

The two traffic-filtering methods directly supported by the Filter complement each other performance-wise and feature-wise:
  • The software firewall is very flexible, but might not be fast enough to handle a full 10 GbE link, especially when dealing with small packets.
    The Filter does not use the connection tracking system specific to stateful firewalls. This ensures a much better filtering and routing performance. However we are unable to estimate the filtering performance you will achieve, as the packet filter's capacity depends on many parameters: CPU type/speed/cache, Linux kernel version, NIC chipset, NIC driver, attack type, server load, routed traffic size, multi-core balance of hardware interrupts, number of existing rules, etc.
    You can find several iptables benchmarks on the web, but most of them are not related to stateless filtering.
  • The hardware packet filter is able to drop 10G traffic at wire-speed without any CPU usage. It is currently only able to filter IP addresses (sources or destinations), so it is not efficient against attacks from spoofed, randomized sources. Counters for the number of dropped packets are not available.
If a DDoS attack saturates the uplink bandwidth or is above the capacity of the filtering server(s), then the Sensor is able to BGP black-hole/null-route the attacked destinations.
Multiple filtering servers can be deployed in a cluster-like architecture when the packets are load-balanced (round-robin).

You can download and use the Filter for 30 days by requesting an evaluation license.
WanGuard Filter licenses can be purchased through the online store.
The answers for several frequently asked questions are listed in the Knowledge Base.
If you need any further information, do not hesitate to contact us.