BYOIP on Microsoft Azure
Azure calls it a custom IP prefix. Bring a /21 to /24, derive Standard public IPs from it and use them on any resource that takes a Standard public IP.
What Azure requires
- Prefix size: /21 to /24 for IPv4, /48 for IPv6.
- Registry: the range is registered with a regional internet registry, such as the RIPE NCC.
- ROA that authorises Microsoft's AS8075.
- Proof of control: a message signed with your certificate, placed in the registry record.
- Limits: five custom prefixes per region by default. A provisioned range can't move to another subscription.
Where you can use it
Public IP prefixes and Standard public IPs derived from your range work on any Azure resource that supports Standard public IPs, and can be covered by DDoS Protection.
Global-tier IPs and Routing Preference IPs can't be derived from a custom prefix.
Steps
- BlockWe lease or sell you a clean /21 to /24.
- RegistryWe create the ROA for AS8075 and add your signed message.
- ProvisionAzure validates the range and creates it in your subscription, not yet advertised.
- CommissionMicrosoft advertises it, first from the provisioning region.
What a /24 costs per month
Azure Standard public IPv4
$934
$0.005 per IP-hour × 256
Leased /24 via BYOIP
$97
RIPE rate, $0.38 per IP
You save
$10,045 / yr
About 90% less
Azure retail price for a Standard static IPv4 address, West Europe, checked October 2026. Azure doesn't charge for custom IP prefixes or the public IPs derived from them; traffic is billed at normal egress rates.
Bringing your IPs to Azure?
Tell us the region and the prefix size you need.