View IP address history - Amazon Virtual Private Cloud

View IP address history

Follow the steps in this section to view the history of an IP address or CIDR in an IPAM scope. You can use the historical data to analyze and audit your network security and routing policies. IPAM automatically retains IP address monitoring data for up to three years.

You can use the IP historical data to search for the status change of IP addresses or CIDRs for the following types of resources:

  • VPCs

  • VPC subnets

  • Elastic IP addresses

  • EC2 instances

  • EC2 network interfaces attached to instances

Important

Although IPAM doesn't monitor Amazon EC2 instances or EC2 network interfaces attached to instances, you can use the IP historical insights feature to search for historical data on EC2 instance and network interface CIDRs.

AWS Management Console

To view the history of a CIDR

  1. Open the IPAM console at https://console.aws.amazon.com/ipam/.

  2. In the navigation pane, choose IP historical insights.

  3. Enter an IPv4 or IPv6 IP address or CIDR. This must be a specific CIDR for the resource.

  4. Choose an IPAM scope ID.

    Note

    If you move a resource from one IPAM scope to another, the previous history record ends and a new history record is created under the new scope.

  5. Choose a date/time range.

  6. If you want to filter the results by VPC, enter a VPC ID. Use this option if the CIDR appears in multiple VPCs.

  7. Choose Search.

Command line

The commands in this section link to the AWS CLI Reference documentation. The documentation provides detailed descriptions of the options that you can use when you run the commands.

To see examples of how you can use the AWS CLI to analyze and audit IP address usage, see Tutorial: View IP address history using the AWS CLI.

The results of the search are organized into the following columns:

  • Sampled end time: Sampled end time of the resource-to-CIDR association within the IPAM scope. Changes are picked up in periodic snapshots, so the end time might have occurred before this specific time.

  • Sampled start time: Sampled start time of the resource-to-CIDR association within the IPAM scope. Changes are picked up in periodic snapshots, so the start time might have occurred before this specific time.

    To help explain the times that you see under Sampled start time and Sampled end time, let’s look at an example use case:

    At 2:00 PM, a VPC was created with CIDR 10.0.0.0/16. At 3:00 PM, you create an IPAM and IPAM pool with CIDR 10.0.0.0/8, and select the auto-import option to allow IPAM to discover and import any CIDRs that fall within the 10.0.0.0/8 IP address range. Because IPAM picks up changes to CIDRs in periodic snapshots, it doesn’t discover the existing VPC CIDR until 3:05 PM. When you search for the ID of this VPC using the IP historical insights feature, the Sampled start time for your VPC is 3:05 PM, which is when IPAM discovered it, not 2:00 PM, which is when you created the VPC. Now, let’s say that you decide to delete the VPC at 5:00 PM. When the VPC is deleted, the CIDR 10.0.0.0/16 that was allocated to the VPC is recycled back into the IPAM pool. IPAM takes its periodic snapshot at 5:05 PM and picks up the change. When you search for the ID of this VPC in IP historical insights, 5:05 PM is the Sampled end time for the VPC’s CIDR, not 5:00 PM, which is when the VPC was deleted.

  • Resource ID: The ID generated when the resource was associated with the CIDR.

  • Name: The name of the resource (if applicable).

  • Compliance status: The compliance status of the CIDR.

    • Compliant: A managed resource complies with the allocation rules of the IPAM pool.

    • Noncompliant: The resource CIDR does not comply with one or more of the allocation rules of the IPAM pool.

      If a VPC has a CIDR that does not meet the netmask length parameters of the IPAM pool, or if the resource is not in the same AWS Region as the IPAM pool, it will be flagged as noncompliant.

    • Unmanaged: The resource does not have a CIDR allocated from an IPAM pool and is not being monitored by IPAM for potential CIDR compliance with pool allocation rules. The CIDR is monitored for overlap.

    • Ignored: The managed resource has been chosen to be exempt from monitoring. Ignored resources are not evaluated for overlap or allocation rule compliance. When a resource is chosen to be ignored, any space allocated to it from an IPAM pool is returned to the pool and the resource will not be imported again through automatic import (if the automatic import allocation rule is set on the pool).

    • -: This resource is not one of the types of resources that IPAM can monitor or manage.

  • Overlap status: The overlap status of CIDR.

    • Nonoverlapping: The resource CIDR does not overlap with another CIDR in the same scope.

    • Overlapping: The resource CIDR overlaps with another CIDR in the same scope. Note that if a resource CIDR is overlapping, it could be overlapping with a manual allocation.

    • Ignored: The managed resource has been chosen to be exempt from monitoring. IPAM does not evaluate ignored resources for overlap or allocation rule compliance. When a resource is chosen to be ignored, any space allocated to it from an IPAM pool is returned to the pool and the resource will not be imported again through automatic import (if the automatic import allocation rule is set on the pool).

    • -: This resource is not one of the types of resources that IPAM can monitor or manage.

  • Resource type

    • vpc: The CIDR is associated with a VPC.

    • subnet: The CIDR is associated with a VPC subnet.

    • eip: The CIDR is associated with an Elastic IP address.

    • instance: The CIDR is associated with an EC2 instance.

    • network-interface: The CIDR is associated with a network interface.

  • VPC ID: The ID of the VPC this resource belongs to (if applicable).

  • CIDR: The CIDR that's associated with this resource.

  • Region: The AWS Region of this resource.

  • Owner ID: The AWS account ID of the user that created this resource (if applicable).