diff --git a/roles/network/tasks/sysd-netd-debian.yml b/roles/network/tasks/sysd-netd-debian.yml
index 77b3243b1..d3fd3b95d 100644
--- a/roles/network/tasks/sysd-netd-debian.yml
+++ b/roles/network/tasks/sysd-netd-debian.yml
@@ -30,8 +30,8 @@
 
 - name: Static IP computing CIDR
   shell: netmask {{ wan_ip }}/{{ wan_netmask }} | awk -F "/" '{print $2}'
-  when: wan_ip != "dhcp"
   register: CIDR
+  when: wan_ip != "dhcp" or gui_static_wan_ip == "undefined"
 
 # ICO will always set gui_static_wan_ip away from the default of 'unset' while
 # gui_static_wan turns dhcp on/off through wan_ip in computed_network and