Azure Virtual Network FAQ #14
Description
Microsoft recommends using the IP range for private networks as recommended by the Internet Assigned Numbers Authority (IANA):
- 0.0.0–10.255.255.255 (10/8 prefix)
- 16.0.0–172.31.255.255 (172.16/12 prefix)
- 168.0.0–192.168.255.255 (192.168/16 prefix)
In addition, in Microsoft Azure, you can’t use the following ranges because they are reserved by the platform:
- 0.0.0/4 (Multicast)
- 255.255.255/32 (Broadcast)
- 0.0.0/8 (Loopback)
- 254.0.0/16 (Link-local)
- 63.129.16/32 (internal domain name service [DNS])
The following IPs are reserved by Microsoft Azure:
- x.x.0: Network address.
- x.x.1: Default gateway.
- x.x.2, x.x.x.3: To map the Microsoft Azure DNS IPs to the VNet space.
- x.x.255: Network broadcast address.
At the time of publishing, following are the recommendations from Microsoft:
- GatewaySubnet: /27 or larger
- AzureBastionSubnet: /27 or larger
- Microsoft Azure NetApp Files Subnet: /28 or higher
Reference: https://learn.microsoft.com/en-us/azure/virtual-network/virtual-networks-faq