oam/examples/ansible/knockd.yml

---

- name: Setup port knocking
  tags:
    - knock
    - knockd
    - port-knocking
  hosts: all
  vars:
    packages:
      - "{{ (ansible_pkg_mgr in ['dnf', 'yum']) | ternary('knock-server', 'knockd') }}"

  handlers:
    - name: Restart knockd
      tags:
        - restart
        - service
      ansible.builtin.service:
        name: knockd.service
        state: restarted
        enabled: true

  tasks:
    - name: Install knockd
      tags:
        - installation
        - package
      become: true
      ansible.builtin.package:
        name: "{{ packages }}"
    - name: Configure knockd
      tags:
        - configuration
      become: true
      notify: Restart knockd
      ansible.builtin.copy:
        dest: /etc/knockd.conf
        content: |
          [options]
            UseSyslog
            Interface = {{ ansible_default_ipv4.alias }}

          [openClose7777]
            sequence      = 2222:udp,3333:tcp,4444:udp
            seq_timeout   = 15
            tcpflags      = syn
            cmd_timeout   = 10
            start_command = /usr/bin/firewall-cmd --add-port=7777/tcp --zone=public
            stop_command  = /usr/bin/firewall-cmd --remove-port=7777/tcp --zone=public
        backup: true
        mode: '0600'