AZ-900 Microsoft Azure Fundamentals 2020

Sign Up Free or Log In to participate!

256 resources attached to a subnet

In the lab you stated that you can attach 256 resources for a /24 subnet. Does this mean that Azure does not count the network ID or broadcast ID or reserve any other IPs within the subnet?

Karan Kaul

Exactly my question as well. Traditionally, in /24 we’ll only have 254 usable IP addresses.

1 Answers

In Azure, whenever you create a subnet, 5 IP Addresses are reserved. So, a /24 will only give you 251 usable IP addresses instead of 256. This is different from traditional networking where only the network and broadcast addresses are reserved.

What are these 5 addresses used for? See below:

x.x.x.0: Network address

x.x.x.1: Reserved by Azure for the default gateway (this is basically the Azure implicit router interface that you don’t see)

x.x.x.2, x.x.x.3: Reserved by Azure to map the Azure DNS IPs to the VNET space

x.x.x.255: Network broadcast address


Thanks Mev, do you have a link to a document that describes that?


Perfect!! Thanks Mev!

Sign In
Welcome Back!

Psst…this one if you’ve been moved to ACG!

Get Started
Who’s going to be learning?