add subnet default route override to forced tunneling

Author: jaidharosenblatt

articles/vpn-gateway/vpn-gateway-forced-tunneling-rm.md

@@ -37,7 +37,7 @@ Forced tunneling in Azure is configured using virtual network custom user-define
   * **On-premises routes:** To the Azure VPN gateway.
   * **Default route:** Directly to the Internet. Packets destined to the private IP addresses not covered by the previous two routes are dropped.
 * This procedure uses user-defined routes (UDR) to create a routing table to add a default route, and then associate the routing table to your VNet subnet(s) to enable forced tunneling on those subnets.
-* Forced tunneling must be associated with a VNet that has a route-based VPN gateway. You need to set a "default site" among the cross-premises local sites connected to the virtual network. Also, the on-premises VPN device must be configured using 0.0.0.0/0 as traffic selectors. 
+* Forced tunneling must be associated with a VNet that has a route-based VPN gateway. Your forced tunneling configuration will override the default route for any subnet in its VNet. You need to set a "default site" among the cross-premises local sites connected to the virtual network. Also, the on-premises VPN device must be configured using 0.0.0.0/0 as traffic selectors. 
 * ExpressRoute forced tunneling is not configured via this mechanism, but instead, is enabled by advertising a default route via the ExpressRoute BGP peering sessions. For more information, see the [ExpressRoute Documentation](https://azure.microsoft.com/documentation/services/expressroute/).
 * When having both VPN Gateway and ExpressRoute Gateway deployed in the same VNet, user-defined routes (UDR) is no longer needed as ExpressRoute Gateway will advertise configured "default site" into VNet.