diff --git a/net-config-standalone.j2.yaml b/net-config-standalone.j2.yaml
index 7f1c4860df..036b3fef76 100644
--- a/net-config-standalone.j2.yaml
+++ b/net-config-standalone.j2.yaml
@@ -92,6 +92,8 @@ conditions:
       equals: [{get_param: StandaloneNetConfigOverride}, {}]
   control_virtual_ip_unset: {equals : [{get_param: [DeployedServerPortMap, 'control_virtual_ip', fixed_ips, 0, ip_address]}, '']}
   public_virtual_ip_unset: {equals : [{get_param: [DeployedServerPortMap, 'public_virtual_ip', fixed_ips, 0, ip_address]}, '']}
+  control_virtual_ip_is_ipv6: {contains: [':', {get_param: [DeployedServerPortMap, 'control_virtual_ip', fixed_ips, 0, ip_address]}]}
+  public_virtual_ip_is_ipv6: {contains: [':', {get_param: [DeployedServerPortMap, 'public_virtual_ip', fixed_ips, 0, ip_address]}]}
 
 resources:
   OsNetConfigImpl:
@@ -135,7 +137,7 @@ resources:
                         list_join:
                         - /
                         - - {get_param: [DeployedServerPortMap, 'control_virtual_ip', fixed_ips, 0, ip_address]}
-                          - '32'
+                          - {if: [control_virtual_ip_is_ipv6, '128', '32']}
                   -
                     if:
                     - public_virtual_ip_unset
@@ -144,7 +146,7 @@ resources:
                         list_join:
                         - /
                         - - {get_param: [DeployedServerPortMap, 'public_virtual_ip', fixed_ips, 0, ip_address]}
-                          - '32'
+                          - {if: [public_virtual_ip_is_ipv6, '128', '32']}
                   routes: {get_param: ControlPlaneStaticRoutes}
                   members:
                   - type: interface
diff --git a/net-config-undercloud.j2.yaml b/net-config-undercloud.j2.yaml
index 79c0d04325..24327dbe69 100644
--- a/net-config-undercloud.j2.yaml
+++ b/net-config-undercloud.j2.yaml
@@ -88,6 +88,8 @@ conditions:
       equals: [{get_param: UndercloudNetConfigOverride}, {}]
   control_virtual_ip_unset: {equals : [{get_param: [DeployedServerPortMap, 'control_virtual_ip', fixed_ips, 0, ip_address]}, '']}
   public_virtual_ip_unset: {equals : [{get_param: [DeployedServerPortMap, 'public_virtual_ip', fixed_ips, 0, ip_address]}, '']}
+  control_virtual_ip_is_ipv6: {contains: [':', {get_param: [DeployedServerPortMap, 'control_virtual_ip', fixed_ips, 0, ip_address]}]}
+  public_virtual_ip_is_ipv6: {contains: [':', {get_param: [DeployedServerPortMap, 'public_virtual_ip', fixed_ips, 0, ip_address]}]}
 
 resources:
   OsNetConfigImpl:
@@ -130,7 +132,7 @@ resources:
                         list_join:
                         - /
                         - - {get_param: [DeployedServerPortMap, 'control_virtual_ip', fixed_ips, 0, ip_address]}
-                          - '32'
+                          - {if: [control_virtual_ip_is_ipv6, '128', '32']}
                   -
                     if:
                     - public_virtual_ip_unset
@@ -139,7 +141,7 @@ resources:
                         list_join:
                         - /
                         - - {get_param: [DeployedServerPortMap, 'public_virtual_ip', fixed_ips, 0, ip_address]}
-                          - '32'
+                          - {if: [public_virtual_ip_is_ipv6, '128', '32']}
                   routes: {get_param: ControlPlaneStaticRoutes}
                   members:
                   - type: interface