[sysctl-fowarding] Enable IP forwarding on routers

plays/firewall.yml

 #!/usr/bin/env ansible-playbook
 ---
-# Deploy iproute2 config file
+# Deploy iproute2 and sysctl config files
 - hosts: crans_routeurs
   roles:
     - iproute2
+    - sysctl-forwarding
 
 # Deploy firewall
 - hosts: crans_routeurs

roles/sysctl-forwarding/tasks/main.yml

+---
+- name: Deploy sysctl configuration
+  template:
+    src: sysctl.d/10-forwarding.conf.j2
+    dest: /etc/sysctl.d/10-forwarding.conf

roles/sysctl-forwarding/templates/sysctl.d/10-forwarding.conf.j2

+{{ ansible_header | comment }}
+
+# Enable packet forwarding for IPv4
+net.ipv4.ip_forward=1
+
+# Enable packet forwarding for IPv6
+#  Enabling this option disables Stateless Address Autoconfiguration
+#  based on Router Advertisements for this host
+net.ipv6.conf.all.forwarding=1