Today Microsoft announced today a new feature called User Defined Routes in Azure.
This addresses what was previously a significant challenge to networking configuration within the Azure topology. User defined routes enables an administrator to configure their own routes within their Azure virtual networking topology.
The route tables are defined for the subnet and then facilitate connectivity for any address prefix, as well as the definition of a default route to tunnel all traffic on-premise, or to an appliance.
Here is the slide that was shared at Microsoft Ignite today on this new feature:
This capability brings a significant new flexibility to the Azure network configuration and provides opportunities that were previously available only on-premise.