Merge pull request #248625 from duongau/duongau-patch-3

ExpressRoute - About ER gateways - add callout about overlapping udr with gatewaysubnet

Author: prmerger-automator[bot]

includes/vpn-gateway-gwudr-warning.md

@@ -9,4 +9,6 @@
  ms.author: cherylmc
  ms.custom: include file
 ---
-User-defined routes with a 0.0.0.0/0 destination and NSGs on the GatewaySubnet **are not supported**. Gateways with this configuration are blocked from being created. Gateways require access to the management controllers in order to function properly. [BGP route propagation](../articles/virtual-network/virtual-networks-udr-overview.md#border-gateway-protocol) should be set to "Enabled" on the GatewaySubnet to ensure availability of the gateway. If BGP route propagation is set to disabled, the gateway won't function.
+- User-defined routes with a 0.0.0.0/0 destination and NSGs on the GatewaySubnet **are not supported**. Gateways with this configuration are blocked from being created. Gateways require access to the management controllers in order to function properly. [BGP route propagation](../articles/virtual-network/virtual-networks-udr-overview.md#border-gateway-protocol) should be set to "Enabled" on the GatewaySubnet to ensure availability of the gateway. If BGP route propagation is set to disabled, the gateway won't function.
+
+- Diagnostics, data path, and control path can be affected if a user-defined route overlaps with the Gateway subnet range or the gateway public IP range.