Azure automatically routes traffic between Azure subnets, virtual networks, and on-premises networks. If you want to change any of Azure’s default routing, you do so by creating a route table.
This blog post shows how to create a route table.
Create a route table
There is a limit to how many route tables you can create per Azure location and subscription.
In the left corner of the portal, select + All services.
Select Networking, then select Route table.
Enter a Name for the route table, select your Subscription, create a new Resource group, or select an existing resource group, select a Location, then select Create.
If you plan to associate the route table to a subnet in a virtual network that is connected to your on-premises network through a VPN gateway, and you disable Virtual network gateway route propagation, your on-premises routes are not propagated to the network interfaces in the subnet.
Create a route
There is a limit to how many routes per route table can create per Azure location and subscription.
Select Routes, under SETTINGS.
Select + Add.
Enter a unique Name for the route within the route table.
Enter the Address prefix, in CIDR notation, that you want to route traffic to. The prefix cannot be duplicated in more than one route within the route table, though the prefix can be within another prefix.
Select a Next hop type.
Enter an IP address for Next hop address. You can only enter an address if you selected Virtual appliance for Next hop type.
Associate a route table to a subnet
A subnet can have zero or one route table associated to it. A route table can be associated to zero or multiple subnets. Since route tables are not associated to virtual networks, you must associate a route table to each subnet you want the route table associated to.
Select Subnets under SETTINGS.
Select Vnet and subnet you want to associate the route table to.