Subnets

Per Microsoft: "Azure reserves 5 IP addresses within each subnet. These are x.x.x.0-x.x.x.3 and the last address of the subnet. x.x.x.1-x.x.x.3 is reserved in each subnet for Azure services.

x.x.x.0: Network address

x.x.x.1: Reserved by Azure for the default gateway

x.x.x.2, x.x.x.3: Reserved by Azure to map the Azure DNS IPs to the VNet space

x.x.x.255: Network broadcast address"*

• source = https://docs.microsoft.com/en-us/azure/virtual-network/virtual-networks-faq