drupal/core/modules/ban/ban.services.yml

services:
  ban.ip_manager:
    class: Drupal\ban\BanIpManager
    arguments: ['@database']
    tags:
      - { name: backend_overridable }
  ban.middleware:
    class: Drupal\ban\BanMiddleware
    arguments: ['@ban.ip_manager']
    tags:
      # Ensure to come before page caching, so you don't serve cached pages to
      # banned users.
      - { name: http_middleware, priority: 250 }