Address recycling
Yet another reason why we need IPv6...
IPv4 address on AWS and other such platforms need to be recycled because there's a shortage of them, if a machine gets killed and they don't remove the DNS records then someone else will soon inherit them. The address allocations are also random and spread all over the address space AWS owns so if your trying to add firewall rules, or determine what the traffic is from a packet capture or logs its painful.
IPv6 allocations are based on blocks per customer, so houseparty will be allocated a large block by AWS and all of their allocations will come from that. If they drop a machine then the address goes dead and won't be allocated to a different customer as it still belongs to houseparty.
Another good example of this absolute mess is Zoom:
https://support.zoom.us/hc/en-us/articles/201362683-Network-Firewall-or-Proxy-Server-Settings-for-Zoom
75 separate spread out ipv4 blocks that belong to aws (and do zoom even control all the addresses in those blocks?), or a single ipv6 block that belongs exclusively to zoom... I know which i'd rather use for monitoring and firewall rule purposes.
Biting the hand that feeds IT
