NGINX App Protect DoS Release 4.0

Here you can find the release information for NGINX App Protect DoS v4.0. NGINX App Protect DoS provides behavioral protection against Denial of Service (DoS) for your web applications.

Release 4.0

January 31, 2023

New Features

  • Distributed Denial of Service (DDoS) protection feature for WebSocket services.
    Refer to the Configuration Example for WebSocket services here.
  • DDoS protection against slow attacks has been improved using machine learning algorithm on all types of traffic.
  • app_protect_dos_monitor directive, which monitors the proxied server, supports a new type of protocol - “WebSocket”.

Supported Packages

App Protect DoS

CentOS 7.4+ / RHEL 7.4+ / UBI7
  • app-protect-dos-28+4.0.1-1.el7.ngx.x86_64.rpm
  • app-protect-dos-28+4.0.1-1.el8.ngx.x86_64.rpm
Debian 11
  • app-protect-dos_28+4.0.1.-1~bullseye_amd64.deb
Ubuntu 18.04
  • app-protect-dos_28+4.0.1-1~bionic_amd64.deb
Ubuntu 20.04
  • app-protect-dos_28+4.0.1-1~focal_amd64.deb
Alpine 3.15
  • app-protect-dos-


  • NGINX Plus R28

Important Notes

  • WebSocket protection requires active monitoring of the protected service. The directive app_protect_dos_monitor is mandatory for these use cases, otherwise, the attack will not be detected.

  • Installing accelerated mitigation feature (install app-protect-dos-ebpf) configures nginx and admd to run with root privileges.

  • Support for proxy_protocol configuration: proxy_protocol monitor parameter should be used when the listen directive of the correspondent server block contains the proxy_protocol parameter.

  • If NGINX App Protect WAF is installed, app protect should be disabled for the location of DoS Live Activity Monitoring API.

    For example:

    location /api {
    app_protect_enable off;
  • Port configuration in app_protect_dos_monitor should correspond to the port, the server listens to. Misconfiguration can potentially cause a false attack declaration.

    For example:

        server {
            listen 8080;
            location / {  app_protect_dos_monitor "";  }
  • gRPC and HTTP/2 protection require active monitoring of the protected service. The directive app_protect_dos_monitor is mandatory for the attack to be detected.

  • TLS fingerprint feature is not used in CentOS 7.4 and RHEL 7 / UBI 7 due to the old OpenSSL version. The required OpenSSL version is 1.1.1 or higher.

  • Monitor directive app_protect_dos_monitor with proxy_protocol parameter can not be configured on Ubuntu 18.04. As a result, gRPC and HTTP/2 DoS protection for proxy_protocol configuration is not supported.

  • Slow attack always mitigates with block action while other types of attacks can also be mitigated with redirection or JS challenges.

  • The recommended option of running NGINX Plus in a Docker Container is with the daemon off flag. It’s mandatory for UBI 8.