Understanding IP addressing and DNS in Azure
When building services in Azure, you sometimes choose to use internal IP addresses and external IP addresses. Internal IP addresses can only communicate internally and use VNETs. Many services can also use public IP addresses, which allow you to communicate with the service from the internet.
Before we delve into public and internal IP addresses, we need to understand the basics of IP addressing in general, and especially the use of subnets and subnet masks.
Understanding subnets and subnet masks
When devices are connected to a TCP/IP-based network, they are provided with an IP address in the notation xxx.xxx.xxx.xxx. Generally, all devices that are on the same local network can communicate with each other without any additional settings.
When devices on different networks need to communicate, they must do so via a router or gateway. Devices use a subnet mask to differentiate between addresses on the local network and those on a remote...