My question is about cloud platforms like AWS or Azure. Whenever we create an instance (VM or VPC), AWS allocates a set of public and private IPs for that instance.

Now the number of user accounts (or EC2 instances) on the AWS are in the order of millions.

How does AWS manage to assign so many public IPs? I understand that once an account is deleted or an instance is deleted, that IP would be reused and reassigned.

But do they have an IP address pool so big of so many IP addresses that can suffice the need of the millions of VMs that are running concurrently? Or there is internal NATing or re-use of IP addresses of some kind?

  • 2
    Many companies have huge pools of IPv4 addresses, and IPv6 addresses are assigned in massive pools.
    – Ron Maupin
    Mar 19 '19 at 19:05
  • Unfortunately, questions about networks not under your direct control are off-topic here.
    – Ron Maupin
    Mar 21 '19 at 1:18

They have millions of IPv4 addresses. Five years ago, Amazon had over 4 million. I'm sure they have bought many more blocks over the years. You can calculate the current number yourself by downloading their latest report.

For comparison, here is Microsoft Azure IP info.

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