1

SCENARIO:

I am running out of free ips in my AWS subnets. I would like to talk to my infra team and request them to create new subnets. But they are asking me list of all ips I have consumed so far and to show how each ip is used

  1. TOTAL IP CAPACITY:

    So I see there are a total of 384 ips available across 8 subnets in 2 VPCs.

  2. FREE IPs:

    Now I can see from the VPC page that there are a total of 126 free ips available.

  3. TOTAL IPs CONSUMED:

    So this means 384-126 = 258 ips have been consumed in this account.

  4. Total # of EC2s:

    I also got a list of all EC2s from the "Tag Editor" page on AWS Console. That list shows a total of 72 EC2s.

  5. DOESN'T ADD UP

    So 258 ips have been consumed as per #3 above

    But there are only 72 EC2s created totally as per #4 above

So who consumed the remaining 258-72 = 186 ips?

Do any other services other than EC2 consume ips?

Where is the disconnect?

1
  • can you add sizes of your subnets and VPCs, not just the number of IPs that AWS reports? That'll help with determining which IP's AWS reserves without creating interfaces that you can see. For the rest, AWS should list the interfaces (but I'll leave that for the answer, not comment)
    – Peter Turner
    May 26 at 14:40
3

There are many AWS services which requires a network interface such as AWS load balancers, Lambda, NAT gateway, VPC endpoints etc. For each AWS load balancer, it may use up to 2 IPs and 1 IP for 1 lambda function. I would recommend to check the network interface section under EC2 service which will show you all the IPs which are currently being used and attached to EC2, Lambda, load balancer or some other service.

NOTE: For each subnet, 5 IP addresses will be reserved by AWS. So, if you have a subnet with /28 subnet mask (16 available IP addresses ), in AWS, you will get only 11 IPs which can be used.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.