diff --git a/network/network.j2 b/network/network.j2
index 8f19bf7a12..7fd798b01b 100644
--- a/network/network.j2
+++ b/network/network.j2
@@ -1,3 +1,6 @@
+{%- if ipv6_override is not defined %}
+{%- set ipv6_override = false %}
+{%- endif %}
 heat_template_version: wallaby
 
 description: >
@@ -6,7 +9,7 @@ description: >
 parameters:
   # the defaults here work for static IP assignment (IPAM) only
   {{network.name}}NetCidr:
-{%- if network.ipv6 or ipv6_override %}
+{%- if network.ipv6|default(false) or ipv6_override %}
     default: "{{network.ipv6_subnet|default(network.ip_subnet|default(""))}}"
 {%- else %}
     default: "{{network.ip_subnet|default("")}}"
@@ -38,14 +41,14 @@ parameters:
     description: The name of the {{network.name_lower}} subnet in Neutron.
     type: string
   {{network.name}}AllocationPools:
-{%- if ":" in network.ip_subnet or network.ipv6 or ipv6_override %}
+{%- if ":" in network.ip_subnet|default("") or network.ipv6|default(false) or ipv6_override %}
     default: {{network.ipv6_allocation_pools|default(network.allocation_pools|default([]))}}
 {%- else %}
     default: {{network.allocation_pools|default([])}}
 {%- endif %}
     description: Ip allocation pool range for the {{network.name_lower}} network.
     type: json
-{%- if ":" in network.ip_subnet or network.ipv6 or ipv6_override %}
+{%- if ":" in network.ip_subnet|default("") or network.ipv6|default(false) or ipv6_override %}
   IPv6AddressMode:
     default: dhcpv6-stateful
     description: Neutron subnet IPv6 address mode
@@ -56,7 +59,7 @@ parameters:
     type: string
 {%- endif %}
   {{network.name}}InterfaceDefaultRoute:
-{%- if network.ipv6 or ipv6_override %}
+{%- if network.ipv6|default(false) or ipv6_override %}
     default: "{{network.gateway_ipv6|default(network.gateway_ip|default(''))}}"
 {%- else %}
     default: "{{network.gateway_ip|default('')}}"
@@ -83,7 +86,7 @@ parameters:
     type: number
 {%- for subnet in network.subnets|default({}) if network.subnets[subnet].enabled|default(true) %}
   {{network.name}}SubnetCidr_{{subnet}}:
-{%-     if network.ipv6 or ipv6_override %}
+{%-     if network.ipv6|default(false) or ipv6_override %}
     default: "{{network.subnets[subnet]['ipv6_subnet']|default(network.subnets[subnet]['ip_subnet']|default(""))}}"
 {%-     else %}
     default: "{{network.subnets[subnet]['ip_subnet']|default("")}}"
@@ -92,7 +95,7 @@ parameters:
       Cidr for the {{network.name_lower}} network's {{subnet}} subnet.
     type: string
   {{network.name}}AllocationPools_{{subnet}}:
-{%-     if ":" in network.subnets[subnet]['ip_subnet'] or network.ipv6 or ipv6_override %}
+{%-     if ":" in network.subnets[subnet]['ip_subnet'] or network.ipv6|default(false) or ipv6_override %}
     default: {{network.subnets[subnet]['ipv6_allocation_pools']|default(network.subnets[subnet]['allocation_pools']|default([]))}}
 {%-     else %}
     default: {{network.subnets[subnet]['allocation_pools']|default([])}}
@@ -101,7 +104,7 @@ parameters:
       Ip allocation pool range for the {{network.name_lower}} network's {{subnet}} subnet.
     type: json
   {{network.name}}InterfaceDefaultRoute_{{subnet}}:
-{%-     if ":" in network.subnets[subnet]['ip_subnet'] or network.ipv6 or ipv6_override %}
+{%-     if ":" in network.subnets[subnet]['ip_subnet'] or network.ipv6|default(false) or ipv6_override %}
     default: "{{network.subnets[subnet]['gateway_ipv6']|default(network.subnets[subnet]['gateway_ip']|default([]))}}"
 {%-     else %}
     default: "{{network.subnets[subnet]['gateway_ip']|default([])}}"
@@ -184,7 +187,7 @@ resources:
 {%- if network.service_net_map_replace|default('') %}
         - tripleo_service_net_map_replace={{network.service_net_map_replace}}
 {%- endif %}
-{%- if network.ipv6 or ipv6_override %}
+{%- if network.ipv6|default(false) or ipv6_override %}
         - tripleo_ipv6=true
 {%- endif %}
 
@@ -205,7 +208,7 @@ resources:
       # All networks have an implicit network segment when created, map this subnet to that segment.
       segment: {get_attr: [{{network.name}}Network, segments, 0, id]}
       ip_version: {if: [is_ipv6, 6, 4]}
-{%- if ":" in network.ip_subnet or network.ipv6 or ipv6_override %}
+{%- if ":" in network.ip_subnet|default("") or network.ipv6|default(false) or ipv6_override %}
       ipv6_address_mode: {get_param: IPv6AddressMode}
       ipv6_ra_mode: {get_param: IPv6RAMode}
 {%- else %}
@@ -253,7 +256,7 @@ resources:
       host_routes: {get_param: {{network.name}}Routes_{{subnet}}}
       segment: {get_resource: {{network.name}}Segment_{{subnet}}}
       ip_version: {if: [is_ipv6, 6, 4]}
-{%- if ":" in network.ip_subnet or network.ipv6 or ipv6_override %}
+{%- if ":" in network.ip_subnet|default("") or network.ipv6|default(false)  or ipv6_override %}
       ipv6_address_mode: {get_param: IPv6AddressMode}
       ipv6_ra_mode: {get_param: IPv6RAMode}
 {%- else %}
diff --git a/network/ports/port_from_pool.j2 b/network/ports/port_from_pool.j2
index 73e5258e9c..5a9f1adb73 100644
--- a/network/ports/port_from_pool.j2
+++ b/network/ports/port_from_pool.j2
@@ -1,3 +1,6 @@
+{%- if ipv6_override is not defined %}
+{%- set ipv6_override = false %}
+{%- endif %}
 heat_template_version: wallaby
 
 description: >
@@ -53,7 +56,7 @@ parameters:
     default: 0
     type: number
   {{network.name}}NetCidr:
-{%- if network.ipv6 or ipv6_override %}
+{%- if network.ipv6|default(false)  or ipv6_override %}
     default: "{{network.ipv6_subnet|default(network.ip_subnet|default(""))}}"
 {%- else %}
     default: "{{network.ip_subnet|default("")}}"