Merge pull request #23085 from neal-timpe/ossmdoc-59

add subdomains to auto route creation

Author: JStickler

service_mesh/service_mesh_day_two/ossm-auto-route.adoc

@@ -30,6 +30,11 @@ spec:
 
 For more information, see xref:../../service_mesh/service_mesh_install/customizing-installation-ossm.adoc#ossm-cr-gateway_customizing-installation-ossm[Istio gateway configuration].
 
+[id="ossm-auto-route-subdomains_{context}"]
+== Subdomains	
+
+{ProductName} creates the route with the subdomain, but {product-title} must be configured to enable it. Subdomains, for example `*.domain.com`, are supported but not by default. Cluster administrators can refer to xref:../../networking/ingress-operator.html#using-wildcard-routes_configuring-ingress[Using wildcard routes] for instructions on how to enable subdomains.
+
 If the following gateway is created:
 
 ----