A key element when deploying the infrastructure in Microsoft Azure is to define the Virtual Network. The administrator must be extra cautious because the definition of the Virtual Network will impact how the future/upcoming connection between the production environment and the Microsoft Azure will communicate.
The Virtual Network is the configuration piece where we define the IP subnets that will be used by our VMs running on Microsoft Azure, it is important to validate how we are going to integrate Microsoft Azure and and on-premises network (Express Route or VPN) and make sure that the networks are unique on both sides of the fence to make sure that we can enable IP routing when time comes.
The creation process is simple, click on + and select Virtual Network.
In the welcome page of the feature, leave Resource Manager selectec, and click on Create.
In the Create Virtual Network blade. We have to define the name of the Virtual Network and address space (in our example here, we will use 10.171.0.0/16), and that is global. After that, we can configure the first subnet, in our case we will use servers and we will use 10.171.10.0/24 for that range.
After that we need to define the subscription, Resource Group and Azure Datacenter location. I recommend creating a Resource Group just for the network purpose.
After creating the Virtual Network, we need to define the DNS that will be used for all new VMs on that segment. In order to do that, click on the newly created Virtual Network and then click on DNS Servers and type in the IPs of your Domain Controllers or DNS Servers.