VNet max size?

Oleg Maltsev 20 Reputation points
2025-04-09T21:41:38.1333333+00:00

From the training materials:

A subnet is a range of IP address in the VNet. You segment VNets into different size subnets. You then deploy Azure resources in a specific subnet. Just like in a traditional network, subnets allow you to segment your VNet address space into segments that are appropriate for the organization's internal network. The smallest supported IPv4 subnet is /29, and the largest is /2 (using CIDR subnet definitions). IPv6 subnets must be exactly /64 in size.

From practice exam:

The maximum number of private IP addresses that you can have on a virtual network is 65,536. A network address prefix length of /16 will give you roughly that many available IP addresses, maximizing a single virtual network.

My question is, what is the biggest VNet you can create, since information does not match? MS Learn material says /2, exam question says /16

This question is related to the following Learning Module

Azure Virtual Network
Azure Virtual Network
An Azure networking service that is used to provision private networks and optionally to connect to on-premises datacenters.
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  1. Marcin Policht 50,495 Reputation points MVP Volunteer Moderator
    2025-04-09T22:09:40.6766667+00:00

    The smallest subnet you can create in an Azure VNet is /29 (for IPv4) - as far as the largest one, that's dependent on the maximum address space allowed for a single VNet is /16. This gives you the total of 65,536 total combinations of 0s and 1s - but you have to account for the 5 IP addresses which are reserved by the platform for every subnet in that VNet - so effectively the total number of IP addresses available in individual subnets within that VNet is always smaller.

    In short, the MS Learn information you are referring to is either simply incorrect (not applicable to Azure VNets).


    If the above response helps answer your question, remember to "Accept Answer" so that others in the community facing similar issues can easily find the solution. Your contribution is highly appreciated.

    hth

    Marcin

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