diff --git a/modules/installation-osp-custom-subnet.adoc b/modules/installation-osp-custom-subnet.adoc
index 3c1f9077a3..d966e1e4de 100644
--- a/modules/installation-osp-custom-subnet.adoc
+++ b/modules/installation-osp-custom-subnet.adoc
@@ -32,3 +32,8 @@ Clusters that use custom subnets have the following limitations:
 By default, the API VIP takes x.x.x.5 and the Ingress VIP takes x.x.x.7 from your network's CIDR block. To override these default values,
 set values for `platform.openstack.apiVIP` and `platform.openstack.ingressVIP` that are outside of the DHCP allocation pool.
 ====
+
+[IMPORTANT]
+====
+The CIDR ranges for networks are not adjustable after cluster installation. Red Hat does not provide direct guidance on determining the range during cluster installation because it requires careful consideration of the number of created pods per namespace.
+====