Azure Public IP Prefix

Azure public IP address prefix is a way to reserve a range of Public IP addresses for public endpoints in Azure. With Public IP Address prefixes, Azure allocates a contiguous range of addresses to a subscription based on the range specified.

Common Scenarios where Azure Public IP Prefixes help

  • Virtual Machine – Assigning well known public IP address list helps in whitelisting a whole range of IP addresses than the individual IPs for firewall perspective 
  • Load Balancers – Helps you simplify your load balancers IP addresses
  • Azure Firewall – This helps you predtermine the firewall IP address


  • Azure allocates the IP addresses based on the size specified 
  • You can’t delete the IP address prefixes if there is a single IP address created 
  • IP address range can’t be modified once its created 
  • IP address prefix can only assign IPs to resources in the same subscription and the region where it’s created.
  • IP range can vary from /31 (2 IP address ) to /24 (256 IP addresses)

How to create a Public IP address prefix in Azure portal

Log-on to Azure portal > All Services > Public IP Prefixes

How to create a public IP prefix

Once IP Prefix is created, You can now create a single IP address from the prefix

Create an IP address from IP Prefix

Assign the Public IP to a VM – In this step, I have created a new VM and selected the Public IP address which we created in previous steps.

Use the IP address created from the prefix