AZ-104 Microsoft Azure Administrator Exam

Differentiate Between Static and Dynamic Public IP Addresses

Public and private IP addresses in Azure can be assigned using either dynamic or static allocation methods. Understanding the differences between these methods is crucial for configuring and managing virtual networks effectively. Each method serves particular scenarios based on how predictable or stable the IP address must remain.

Dynamic IP Addresses

Dynamic IP addresses are assigned by default in Azure. For public IP addresses, Azure assigns the address from a range unique to each Azure region. These addresses can change when a virtual machine is stopped and then started again, which means they’re not fixed. For private IP addresses, Azure reserves the first four addresses in each subnet and assigns the next available unassigned address. This private address might change if the network interface is deleted, assigned to a different subnet, or the allocation method is switched to static.

Key points about dynamic IP addresses include:

• Public IP: It can change with VM restarts.
• Private IP: It assigns the next available address in the subnet.
• Default method: Dynamic is often set as the default allocation method.

Static IP Addresses

Static IP addresses can be optionally assigned to both public and private IP configurations. For public IP addresses, Azure assigns the address from a regional range, and this address remains the same until you delete the resource or alter the allocation method. For private IP addresses, you select and assign a fixed address from the subnet’s range, and it remains fixed unless the network interface changes or you delete it.

Key points about static IP addresses include:

• Public IP: Address stays fixed till manually deleted or allocation method changes.
• Private IP: Address remains unchanged unless network interface alteration occurs.
• Optional method: Despite being optional, static allocation provides crucial stability.

Use Cases

Dynamic IP addresses are suitable for scenarios where IP stability is non-essential, like development and testing environments where changes are frequent, and stability isn’t mandatory. Static IP addresses, on the other hand, are necessary in production environments where consistent IP addresses matter. They are crucial for applications reliant on DNS settings, SSL certificates, and firewall rules that need predetermined values.

In summary, deciding between dynamic and static IP addresses hinges on your Azure environment's specific requirements. Understanding these allocation methods will ensure proper configuration and management of your virtual networks, providing flexibility or consistency as your operations demand.