Today, AWS announced the launch of a new IPAM feature called Bring-Your-Own-ASN (BYOASN) that lets you bring your own Autonomous System Number (ASN) to AWS, and use it to advertise your IP addresses from AWS. If your applications are using trusted IP addresses and ASNs that your partners or customers have allow listed in their network, you can now run these applications in AWS without requiring your partners or customers to change their allow lists.
Source:: Amazon AWS